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28 tháng 2 2019

giúp mk nhanh nhé

ai nhanh mk tk cho

28 tháng 2 2019

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

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

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

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

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

10 tháng 8 2016

1)

\(2\frac{1}{4}x-9\frac{1}{4}=-7\frac{1}{4}\)

\(2\frac{1}{4}x=\left(-7\frac{1}{4}\right)+9\frac{1}{4}\)

\(2\frac{1}{4}x=2\)

\(x=2:2\frac{1}{4}\)

\(x=\frac{8}{9}\)

Vậy \(x=\frac{8}{9}\)

20 tháng 7 2016

Dấu. là dấu nhân

20 tháng 7 2016

\(A=\left(9\frac{3}{4}:5,2+x.2\frac{7}{24}\right):1\frac{9}{16}=6\)

\(A=\left(9\frac{3}{4}:5,2+x.2\frac{7}{24}\right)=\frac{75}{8}\)

 \(A=\left(2\frac{7}{24}.\frac{9}{11}+x.2\frac{7}{24}\right)=\frac{75}{8}\)

\(A=\left[2\frac{7}{24}.\left(\frac{9}{11}+x\right)\right]=\frac{75}{8}\)

\(A=\frac{9}{11}+x=\frac{45}{11}\)

\(x=\frac{45}{11}-\frac{9}{11}\)

\(x=\frac{36}{11}\)

30 tháng 5 2015

=>4x+(1/2+1/4+1/8+1/16)=1

<=>4x+15/16=1

=>4x=1/16

=>x=1/16:4=1/64

vậy x=1/64

 

\(\left(x+\frac{1}{2}\right)+\left(x+\frac{1}{4}\right)+\left(x+\frac{1}{8}\right)+\left(x+\frac{1}{16}\right)=1\)

\(\Rightarrow\left(x+x+x+x\right)+\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\right)=1\)

\(\Rightarrow4x+\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{8}+\frac{1}{8}-\frac{1}{16}\right)=1\)

\(\Rightarrow4x+\left(1-\frac{1}{16}\right)=1\)

\(\Rightarrow4x+\frac{15}{16}=1\)

\(\Rightarrow4x=1-\frac{15}{16}\)

\(\Rightarrow x=\frac{1}{16}:4\)

\(\Rightarrow x=\frac{1}{64}\)

vậy \(x=\frac{1}{64}\)

10 tháng 4 2016

\(x=\frac{903}{391}\)

Bài này sử dụng MTCT đó bạn!

10 tháng 4 2016

903/391 mình nghĩ vậy

23 tháng 7 2015

a) \(\frac{1}{15}+\frac{1}{35}+...+\frac{1}{195}\)

\(\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{13.15}\)

\(\frac{1}{2}.\left(\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{13.15}\right)\)

\(\frac{1}{2}.\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{13}-\frac{1}{15}\right)\)

\(\frac{1}{2}.\left(\frac{1}{3}-\frac{1}{15}\right)\)

\(\frac{1}{2}.\frac{4}{15}\)

\(\frac{2}{15}\)