Làm bài 6 thôi nhé =)))

6. Số học sinh lớp 6A tương ứng với phân số 1/1 = 1

=> số học sinh trung bình ứng với phân số là: 1 - 1/3 - 2/5 = 4/15

Số học sinh lớp 6A có là: 12 : 4/15 = 45 (em)
Đ/s:..

1/ Các ước nguyên của 5 là: -5; -1; 1; 5

2/ Ta có: \(\frac{3}{20}=\frac{3}{2}.\frac{1}{10}=\frac{3}{2}.\frac{10}{100}=3.5.\frac{1}{100}=15.\frac{1}{100}\)

=> \(\frac{3}{20}=15\%\)

3/ 

a/ 2.x-2005=1945 => 2x=2005+1995 => 2x=3950

=> x=3950:2

=> x=1975

b/ \(\frac{3}{10}.x=\frac{3}{5}\)

=> \(x=\frac{3}{5}:\frac{3}{10}\) => \(x=\frac{3}{5}.\frac{10}{3}\)

=> x=2

4/ (-16).67+33.(-16)=(-16)(67+33)=(-16).100=-1600

tôi sẽ làm bài còn lại

1. Ư ( 5 ) = { 1 ; -1 ; 5 ; -5 }

2. phân số \(\frac{3}{20}\)dưới dạng phần trăm là : \(\frac{3.100}{20}\%\)= \(15\%\)

3. a ) 2 . a - 2005 = 1945

2 . a = 3950

=> a = 1975

b) \(\frac{3}{10}.x=\frac{3}{5}\)

\(\Rightarrow x=\frac{3}{5}:\frac{3}{10}\)

\(\Rightarrow x=2\)

4. ( -16 ) x 67 + ( -16 ) x 33 

= ( -16 ) x ( 67 + 33 )

= ( -16 ) x 100

= -1600

5. \(A=\frac{1}{5}+\frac{1}{9}+\frac{12}{15}-\frac{10}{9}+\frac{2015}{2016}\)

\(A=\left(\frac{1}{5}+\frac{12}{15}\right)+\left(\frac{1}{9}-\frac{10}{9}\right)+\frac{2015}{2016}\)

\(A=1+\left(-1\right)+\frac{2015}{2016}\)

\(A=0+\frac{2015}{2016}\)

\(A=\frac{2015}{2016}\)

\(\frac{3}{4}.\frac{8}{9}.\frac{15}{16}.\frac{24}{25}...\frac{63}{64}\)

\(=\frac{1.3}{2.2}.\frac{2.4}{3.3}.\frac{3.5}{4.4}.\frac{4.6}{5.5}...\frac{7.9}{8.8}\)

\(=\frac{1.3.2.4.3.5.4.6...7.9}{2.2.3.3.4.4.5.5...8.8}\)

\(=\frac{1.9}{2.8}=\frac{9}{16}\)

Hê lô

a,\(\frac{4}{3}\)x \(\frac{9}{8}\)x \(\frac{16}{15}\)x \(\frac{25}{24}\)

= \(\frac{5}{3}\)

b, \(\frac{4}{3}\)x \(\frac{9}{8}\)x \(\frac{16}{15}\)x \(\frac{25}{24}\)x \(\frac{36}{35}\)x \(\frac{49}{48}\)x \(\frac{64}{63}\)x \(\frac{81}{80}\)

= \(\frac{9}{5}\)

chi tiết hơn đc k bn

chi tiết hơn đi bạn

giúp mk nhanh nhé

ai nhanh mk tk cho

B1

a) \(1-\left(5\frac{3}{8}+x-7\frac{5}{24}\right):16\frac{2}{3}=0\)

\(1-\left(\frac{43}{8}+x-\frac{173}{24}\right):\frac{50}{3}=0\)

\(1-\left(x-\frac{11}{6}\right).\frac{3}{50}=0\)

\(\left(x-\frac{11}{6}\right).\frac{3}{50}=1-0\)

\(\left(x-\frac{11}{6}\right).\frac{3}{50}=1\)

\(x-\frac{11}{6}=1:\frac{3}{50}\)

\(x-\frac{11}{6}=\frac{50}{3}\)

\(x=\frac{50}{3}+\frac{11}{6}\)

\(x=\frac{37}{2}\)

b) \(\frac{3}{5}+\frac{5}{7}:x=\frac{1}{3}\)

\(\frac{5}{7}:x=\frac{1}{3}-\frac{3}{5}\)

\(\frac{5}{7}:x=-\frac{4}{15}\)

\(x=\frac{5}{7}:\left(-\frac{4}{15}\right)\)

\(x=-\frac{75}{28}\)

c) \(\left(4\frac{1}{2}-\frac{2}{5}.x\right):\frac{7}{4}=\frac{11}{9}\)

\(\left(\frac{9}{2}-\frac{2}{5}.x\right):\frac{7}{4}=\frac{11}{9}\)

\(\frac{9}{2}-\frac{2}{5}.x=\frac{11}{9}.\frac{7}{4}\)

\(\frac{9}{2}-\frac{2}{5}.x=\frac{11}{2}\)

\(\frac{2}{5}.x=\frac{9}{2}-\frac{11}{2}\)

\(\frac{2}{5}.x=-1\)

\(x=-1:\frac{2}{5}\)

\(x=-\frac{5}{2}\)

B2

a) \(\left(\frac{1}{2}+\frac{1}{3}+\frac{2}{6}\right).24:5-\frac{9}{22}:\frac{15}{121}\)

\(=\left(\frac{3}{6}+\frac{2}{6}+\frac{2}{6}\right).24:5-\frac{9}{22}.\frac{121}{15}\)

\(=\frac{7}{6}.24:5-\frac{33}{10}\)

\(=28:5-\frac{33}{10}\)

\(=\frac{28}{5}-\frac{33}{10}\)

\(=\frac{56}{10}-\frac{33}{10}\)

\(=\frac{23}{10}\)

b) \(\frac{5}{14}+\frac{18}{35}+\left(1\frac{1}{4}-\frac{5}{4}\right):\left(\frac{5}{12}\right)^2\)

\(=\frac{25}{70}+\frac{36}{70}+\left(\frac{5}{4}-\frac{5}{4}\right):\frac{25}{144}\)

\(=\frac{61}{70}+0:\frac{25}{144}\)

\(=\frac{61}{70}+0\)

\(=\frac{61}{70}\)

B=\(\frac{1}{3}+\frac{-0,175+\frac{5}{11}}{0,2625-\frac{15}{22}}\)

B=\(\frac{1}{3}+\frac{\frac{123}{440}}{-\frac{369}{880}}\)

B=\(0,2161148416\)

 Thay x vào ta có: 

\(B=\frac{1}{3}+\frac{0,2-0,375+\frac{5}{11}}{-0,3+\frac{9}{16}-\frac{15}{22}}\)

\(B=\frac{1}{3}+\frac{\frac{2}{10}-\frac{375}{1000}+\frac{5}{11}}{-\frac{3}{10}+\frac{9}{16}-\frac{15}{22}}\)

\(B=\frac{1}{3}+\frac{\frac{1}{5}-\frac{3}{8}+\frac{5}{11}}{-\frac{3}{10}+\frac{9}{16}-\frac{15}{22}}\)

\(B=\frac{1}{3}+\frac{\frac{123}{440}}{\frac{-369}{880}}\)

\(B=\frac{1}{3}+\frac{123}{440}.\frac{880}{-369}\)

\(B=\frac{1}{3}+\frac{-2}{3}\)

\(B=\frac{-1}{3}\)

Vậy...

c1

a,3/15 = 3:3/15:3  = 15 

33/44 = 33:11/44:11 = 34 

2/8 = 2:2/8:2 = 1/4 

b,9/12 =9:3/12:3  = 34 

24/36 =24:12/36:12 = 23 

3/8 = 3:1/8:1 = 3/8 

c2

a) =12x(4+6)/24

= 12x10/24

=120/24

=5

b,16x8-16x2/12x4

=16x(8-2)/48

=16x6/48

=2

c3

5/8=45/72

20/15=4/3=96/72

24/32=3/4=54/72

15/18=5/6=60/72

77/99=7/9=56/72

c4

2/3=2/3

12/15=4/5

24/18=4/3

16/48=1/3

75/100=3/4

30/45=2/3

12/36=1/3

20/15=4/3

các phân số lớn hơn 1 luôn có mẫu số bé hơn tử số 

vậy các số lớn hơn 1 là  24/18,20/15

k mk nha thank mọi ng'

a, \(\frac{3}{15}=\frac{1}{5}=\frac{4}{20}\);   \(\frac{33}{44}=\frac{3}{4}=\frac{15}{20}\);       \(\frac{2}{8}=\frac{1}{4}=\frac{5}{20}\)

b, \(\frac{9}{12}=\frac{3}{4}=\frac{18}{24}\);     \(\frac{24}{36}=\frac{2}{3}=\frac{16}{24}\);      \(\frac{3}{8}=\frac{9}{24}\)

Bài 2 :

a,\(\frac{12x4+12x6}{24}=\frac{12x\left(4+6\right)}{24}=\frac{1x10}{2}=\frac{10}{2}=\frac{5}{1}\)

b, \(\frac{16x8-16x2}{12}=\frac{16x\left(8-2\right)}{12}=\frac{8x6}{6}=\frac{8}{1}\)

bài 1

a,3/15 = 3:3/15:3  = 15 

33/44 = 33:11/44:11 = 34 

2/8 = 2:2/8:2 = 1/4 

b,9/12 =9:3/12:3  = 34 

24/36 =24:12/36:12 = 23 

3/8 = 3:1/8:1 = 3/8 

thu gọn 7^3*7^5

Oh no nhiều kí tự đặc biệt quá

dễ quá mình ko làm  đc