C1 ( 9 : 9 ) x ( 9 : 9 ) + 9

C2 ( 9 x 9 ) : ( 9 x 9 ) + 9

ko cần giải thích đâu nha

giúp mik thêm 3cachs khác đc ko ạ

PHÉP CỘNG – PHÉP NHÂN:

Tổng hai số tự nhiên a, b:

a + b = c  

trong đó : a, b : số hạng; c : tổng

Tích hai số tự nhiên A, B:

A . B = C 

trong đó : A, B : thừa số; C : tích.

Tính chất của phép cộng – phép nhân:

Tính giao hoán :

a + b = b + a

a . b = b . a

Tính kết hợp :

(a + b) + c = a + (b + c)

(a . b) . c = a . (b . c)

Cộng số 0 :

a + 0 = a

nhân với số 1 :

a . 1 = a

tính phân phối :

a . (b + c) = a . b + a . c

PHÉP TRỪ  ( – )  

 a – b = c

trong đó : a : số bị trừ; b : số trừ ; c: hiệu

PHÉP CHA :

Cho hai số tự nhiên a, b trong đó b  0, ta luôn tìm được hai số tự nhiên q và r duy nhất sao cho :

a = b . q + r với 0 < r < b.

Nếu r = 0 thì ta có phép chia hết. kí hiệu : 

a  b

Nếu r ≠ 0 thì ta có phép chia dư. a : b = q dư r

Mik nói tính chất phân số ko phải số tự nhiên nên bạn Thắng sửa lại giúp mik nhé!

Mong bạn đọc kĩ đề giùm mik!Cảm ơn bạn nha!~

Phép nhân phân số

1

Nhân tử số của các phân số với nhau. Tử số là số nằm phía trên của phân số, còn mẫu số là số nằm phía dưới. Bước đầu tiên khi tiến hành nhân phân số là viết chúng thành hàng ngang để các tử số và mẫu số nằm gần nhau. Ví dụ: bạn muốn thực hiện phép nhân 1/2 và 12/48, trước hết bạn cần tìm tích số của hai tử số 1 và 12. 1 x 12 = 12. Bạn có tử số của đáp án là 12.

2

Tiếp tục nhân mẫu số. Làm tương tự như khi bạn tìm tích số của các tử số. Lấy 2 nhân với 48. 2 x 48 = 96. Đây là mẫu số của đáp án. Vậy, phân số mới sẽ là 12/96.

3

Rút gọn phân số. Bước cuối cùng là rút gọn kết quả nếu phân số đó vẫn chưa tối giản. Để rút gọn một phân số, bạn cần tìm ước chung lớn nhất (ƯCLN) của tử số và mẫu số trong phân số đó. ƯCLN là số lớn nhất mà cả tử số và mẫu số đều chia hết. Trong ví dụ này, 96 có thể chia hết cho 12. Ta có: 12 chia 12 được 1, 96 chia 12 được 8. Vậy, 12/96 ÷ 12/12 = 1/8.Nếu cả hai đều là số chẵn, bạn có thể bắt đầu bằng cách chia chúng cho 2 và cứ thế tiếp tục. 12/96 ÷ 2/2 = 6/48 ÷ 2/2 = 3/24. Đến đây, dễ dàng nhận ra rằng 24 chia hết được cho 3, vậy bạn có thể đem chia cả tử số và mẫu số cho 3 để có được đáp án là 1/8. 3/24 ÷ 3/3 = 1/8.

Phương pháp2

Phép chia phân số

1

Đảo ngược tử số và mẫu số của phân số thứ hai và đổi dấu chia thành dấu nhân. Ví dụ, ta có phép tính 1/2 ÷ 18/20. Đầu tiên, nghịch đảo 18/20 để được phân số 20/18, sau đó đổi dấu chia thành dấu nhân. Phép tính sẽ được viết lại như sau: 1/2 ÷ 18/20 = 1/2 x 20/18.

2

Tiếp tục, nhân tử số với nhau để tìm tử, nhân mẫu số với nhau để tìm mẫu, rồi rút gọn đáp án. Làm tương tự như phép nhân phân số. Nhân hai tử số với nhau, 1 và 20, ta có tử số của đáp án là 20. Nhân hai mẫu số với nhau, 2 và 18, ta có mẫu số của đáp án là 36. Kết quả tạm thời là 20/36. Rút gọn phân số bằng cách chia cả tử và mẫu cho ƯCLN là 4. Vậy, kết quả cuối cùng là 20/36 ÷ 4/4 = 5/9.

ok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok okok ok ok

a, Muốn quy đồng mẫu số hai phân số:

Ta lấy mẫu số thứ nhất nhân với tử số và mẫu số của phân số thứ hai và ngược lại

b, Muốn cộng trừ hai phân số khác mẫu số

Ta đi quy đồng mẫu số các phân số ( như đã nói ở trên ) rồi thực hiện cộng, trừ tử số

c, Muốn nhân chia hai phân số:

Nhân: Ta lấy tử số nhân tử số, mẫu số nhân mẫu số

Chia: Ta lấy phân số thứ nhất nhân với phân số thứ hai đảo ngược

a.Muốn quy đồng mẫu số 2 phân số,ta làm như sau :

- Lấy tử số và mẫu số phân số thứ nhất nhân với mẫu số của phân số thứ 2.

- Lấy tử số và mẫu số phân số thứ 2 nhân với mẫu số của phân số thứ nhất.

b/Muốn cộng ( trừ )2 phân số khác mẫu số thì ta phải thực hiện quy đồng mẫu số.

c/ Muốn nhân 2 phân số ta lấy tử nhân tử,mẫu nhân mẫu.

 Muốn chia 2 phân số ta lấy phân số thứ nhất nhân với phân số thứ 2 đảo ngược.

a/ Muốn quy đồng mẫu số nhiều phân số với số mẫu dương ta làm như sau:

Bước 1: Tìm 1 bội chung của các mẫu ( thường là BCNN ) để làm mẫu chung.

Bước 2: Tìm thừa số phụ của mỗi mẫu ( bằng cách chia mẫu chung cho từng mẫu )

Bước 3: Nhân tử và mẫu của mỗi phân số với thừa số phụ tương ứng.

b/ Muốn cộng hai phân số cùng mẫu, ta cộng các tử và giữ nguyên mẫu

Muốn cộng hai phân số không cùng mẫu, ta viết chúng dưới dạng hai phân số cùng 1 mẫu rồi cộng các tử và giữ nguyên mẫu chung.

Muốn trừ hai phân số, ta cộng số bị trừ với số đối của số trừ.

c/ Muốn nhân hai phân số, ta nhân các tử với nhau và nhân các mẫu với nhau.

Muốn chia 1 phân số hay 1 số nguyên cho một phân số, ta nhân số bị chia với số nghịch đảo của số đó.

Nhớ k cho mình nhé!

Câu : Muốn trừ hai phân số không cùng mẫu, ta quy đồng mẫu hai phân số, rồi

A. Trừ hai phân số đó.                                 B. Cộng hai phân số đó.

C. Nhân hai phân số đó.                              D. Chia hai phân số đó.

Câu 6: Muốn nhân hai phân số, ta:

A. nhân các tử với nhau và nhân các mẫu với nhau.

B. nhân các tử với nhau và giữ nguyên mẫu.

C. nhân các tử với nhau và cộng các mẫu với nhau.

D. nhân các tử với nhau và chia các mẫu với nhau.

Câu 7: Muốn nhân một số nguyên với một phân số, ta nhân số nguyên đó với

A. tử của phân số và giữ nguyên mẫu.                  B. mẫu của phân số và giữ nguyên tử.

C. tử của phân số.                                                     D. mẫu của phân số

Câu 8: Muốn chia một phân số cho một phân số khác 0, ta

A. nhân số bị chia với phân số nghịch đảo của số chia

B. chia số bị chia với phân số nghịch đảo của số chia

C. nhân số bị chia với phân số đối của số chia

D. chia các tử với nhau và chia các mẫu với nhau.

A

A

A

A

Câu : Muốn trừ hai phân số không cùng mẫu, ta quy đồng mẫu hai phân số, rồi

A. Trừ hai phân số đó.                                 B. Cộng hai phân số đó.

C. Nhân hai phân số đó.                              D. Chia hai phân số đó.

Câu 6: Muốn nhân hai phân số, ta:

A. nhân các tử với nhau và nhân các mẫu với nhau.

B. nhân các tử với nhau và giữ nguyên mẫu.

C. nhân các tử với nhau và cộng các mẫu với nhau.

D. nhân các tử với nhau và chia các mẫu với nhau.

Câu 7: Muốn nhân một số nguyên với một phân số, ta nhân số nguyên đó với

A. tử của phân số và giữ nguyên mẫu.                  B. mẫu của phân số và giữ nguyên tử.

C. tử của phân số.                                                     D. mẫu của phân số

Câu 8: Muốn chia một phân số cho một phân số khác 0, ta

A. nhân số bị chia với phân số nghịch đảo của số chia

B. chia số bị chia với phân số nghịch đảo của số chia

C. nhân số bị chia với phân số đối của số chia

D. chia các tử với nhau và chia các mẫu với nhau.

Trả lời ; 

1 + 1 = 2

#hok tút#

the nao la hoc vay cac ban

gọi tử là a 

Ta có :\(\frac{a+16}{7.5}=\frac{a}{7}\)

          \(\Rightarrow\frac{a+16}{7.5}=\frac{a.5}{7.5}\)

     => a+16 = a .5

        a + 16 = a.4 + a 

=> 16 = a . 4 

=> a = 16 : 4 

   a = 4

 Vây ...............

a = 4 đó bạn , mình học bài này rồi