\(\frac{21^2.14.125}{35^5.6}=\frac{\left(3.7\right)^2.2.7.5^3}{\left(5.7\right)^5.2.3}=\frac{3^2.7^3.2.5^3}{5^5.2.3.7^5}=\frac{3.}{5^2.7^2}=\frac{3}{1225}\)

b,

\(\frac{72^3.54^2}{108^4}=\frac{\left(2^3.3^2\right)^3.\left(2.3^3\right)^2}{\left(2^2.3^3\right)^4}=\frac{2^{11}.3^{12}}{2^8.3^{12}}=2^3=8\)

Ai là sky thì tick cho tui nha,ko tick ko phải là sky của sếp Tùng.

thấy mà buồn ngủ quá bạn à 

a, 105
b,8
c,8
d3
lam rui nho tik nha.khi nao ra mk lam tip cho

\(\frac{2^{12}.13+2^{12}.65}{2^{10}.104}+\frac{3^{10}.11+3^{10}.5}{3^9.2^4}\)

\(\Rightarrow\frac{2^{12}.\left(13+65\right)}{2^{10}.104}+\frac{3^{10}.\left(11+5\right)}{3^9.2^4}\)

\(\Rightarrow\frac{2^{12}.78}{2^{10}.104}+\frac{3^{10}.2^4}{3^9.2^4}\)

\(=\frac{2^2.3}{4}+3\)

\(=3+3=6\)

B=3^10.11+3^10.5/3^9.2^4

  = 3^10( 11+5)/3^9.16

  = 3^10.16/3^9.16

  = 3^10/3^9

  = 3

Vậy B = 3 (1)

C = 2^10.13+2^10.65/2^8.104

   = 2^10(13+65)/2^8.2^2.26

   = 2^10.78/2^10.26

   = 78/26

   = 3

Vậy C = 3 (2)

Từ (1) v (2) suy ra B=C

cách làm :

câu B 

ta thấy  có 2 lần 2¹⁰ xuất hiện trên 1 phần tử

ta gộp lại như sau :

2¹⁰ x ( 13 + 65 ) cho dễ 

còn câu A 

ta không thể tóm gọn nên phải tính như bình thường 

A  = 649539 + 45  /  648

A = 1002 . 44444444444444444

hay 649584 / 648

B = 0 + 66560 / 2912

B  = 22 . 8571428571

hay 66560 / 2912

Đ/s : .........

nhé !

cho mình sửa lại câu B  

B  =  1024 x ( 13 + 65 ) / 2912

B =   79872 / 2912

a.

\(\frac{2^{10}\times13+2^{10}\times65}{2^8\times104}=\frac{2^{10}\times\left(13+65\right)}{2^8\times104}=\frac{2^2\times78}{104}=\frac{4\times78}{104}=\frac{312}{104}=3\)

b.

\(\left(1+2+...+100\right)\times\left(1^2+2^2+...+10^2\right)\times\left(65\times111-15\times37\times13\right)\)

\(=\left(1+2+...+100\right)\times\left(1^2+2^2+...+10^2\right)\times\left(7215-7215\right)\)

\(=\left(1+2+...+100\right)\times\left(1^2+2^2+...+10^2\right)\times0\)

= 0

a. 3

b. 0

b)

\(\frac{2^{12}.13+2^{12}.65}{2^{10}.104}+\frac{3^{10}.11+3^{10}.5}{3^9.2^4}\)

\(=\frac{2^{10}\left(4.13+4.65\right)}{2^{10}.104}+\frac{3^9\left(11.3+5.3\right)}{3^9.16}\)

\(=\frac{312}{104}+\frac{48}{16}=3+3=6\)

a) \(A=4+2^2+2^3+2^4+....+2^{20}\)

\(\Rightarrow2A=2^3+2^3+2^4+.....+2^{21}\)

\(\Rightarrow2A-A=\left(2^3+2^3+2^4+....+2^{21}\right)-\left(2^2+2^3+2^4+...+2^{20}\right)\)

\(\Rightarrow A=2^3+2^{21}-\left(2^2+2^2\right)\)

\(\Rightarrow A=2^{21}\)

\(\text{Vì }2^{21}⋮2^7\Rightarrow A⋮128\)

b) \(\frac{2^{12}.13+2^{12}.65}{2^{10}.104}+\frac{3^{10}.11+3^{10}.5}{3^9.2^4}\)

\(=\frac{2^{12}\left(13+65\right)}{2^{10}.2^3.13}+\frac{3^{10}\left(11+5\right)}{3^9.2^4}\)

\(=\frac{2^{12}.78}{2^{13}.13}+\frac{3^{10}.16}{3^9.16}=\frac{6}{2}+\frac{3^{10}}{3^9}\)

\(=3+3=6\)