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13 tháng 8 2020

a) \(\frac{3}{5}-\frac{3}{5}(\frac{8}{6}-\frac{3}{6})=\frac{3}{5}-\frac{3}{5}\times\frac{5}{6}=\frac{3}{5}-\frac{1}{2}=\frac{6}{10}-\frac{5}{10}=\frac{1}{10}\)\(\frac{1}{10}\)

b)\(\sqrt{\frac{9}{100}}-\sqrt{0,25}+1,2=\frac{3}{10}-\frac{1}{2}+\frac{6}{5}=\frac{3}{10}-\frac{5}{10}+\frac{12}{10}=1\)

9/10-0,5+1,2

0,4+1,2

1,6

3/5-3/5.(5/6)^2

3/5-3/5.25/36

3/5.(1-25/36)

3/5.11/36

11/60

26 tháng 10 2020

a) \(\frac{3+2\sqrt{3}}{\sqrt{3}}+\frac{2+\sqrt{2}}{1+\sqrt{2}}-2+\sqrt{3}\)

\(=\frac{\sqrt{3}.\left(\sqrt{3}+2\right)}{\sqrt{3}}+\frac{\sqrt{2}.\left(\sqrt{2}+1\right)}{1+\sqrt{2}}-2+\sqrt{3}\)

\(=\sqrt{3}+2+\sqrt{2}-2+\sqrt{3}\)

\(=2\sqrt{3}+\sqrt{2}\)

b) \(\frac{-3}{2}.\sqrt{9-4\sqrt{5}}+\sqrt{\left(-4\right)^2.\left(1+\sqrt{5}\right)^2}\)

\(=\frac{-3}{2}.\sqrt{5-4\sqrt{5}+4}+\sqrt{4^2.\left(1+\sqrt{5}\right)^2}\)

\(=\frac{-3}{2}.\sqrt{\left(\sqrt{5}-2\right)^2}+\sqrt{4^2}.\sqrt{\left(1+\sqrt{5}\right)^2}\)

\(=\frac{-3}{2}.\left|\sqrt{5}-2\right|+4.\left|1+\sqrt{5}\right|\)

\(=\frac{-3}{2}.\left(\sqrt{5}-2\right)+4\left(1+\sqrt{5}\right)\)

\(=\frac{-3\sqrt{5}}{2}+3+4+4\sqrt{5}\)

\(=\frac{-3\sqrt{5}}{2}+4\sqrt{5}+7\)

\(=\frac{-3\sqrt{5}}{2}+\frac{8\sqrt{5}}{2}+\frac{14}{2}\)

\(=\frac{-3\sqrt{5}+8\sqrt{5}+14}{2}=\frac{14+5\sqrt{5}}{2}\)

\(a,\frac{-5}{9}.\left(\frac{3}{10}-\frac{2}{5}\right)\)

\(=\frac{-5}{9}.\frac{-1}{10}\)

\(=\frac{1}{18}\)

\(b,2^8:2^5+3^3.2-12\)

\(=2^3+9.2-12\)

\(=8+18-12\)

\(=26-12\)

\(=14\)

Câu c,d em chưa học nên không biết làm ạ, mong mọi người thông cảm!!!

Sửa lại câu b

\(=2^3+27.2-12\)

\(=8+54-12\)

\(=62-12\)

\(=50\)

12 tháng 12 2019

re thế này mà k biết làm 

22 tháng 9 2021

1.a) \(\left(31\frac{6}{13}+5\frac{9}{41}\right)-36\frac{6}{13}=\left(31+\frac{6}{13}+5+\frac{9}{41}\right)-\left(36+\frac{6}{13}\right)\)

\(=\left(36+\frac{6}{13}-\frac{9}{41}\right)-\left(36+\frac{6}{13}\right)=\left(36+\frac{6}{13}\right)-\left(36+\frac{6}{13}\right)-\frac{9}{41}=-\frac{9}{41}\)

b) \(\frac{5}{3}+\left(-\frac{2}{7}\right)-\left(-1,2\right)-\left|1.4-0,2\right|\)

\(=\frac{5}{3}-\frac{2}{7}+1,2-1,2=\frac{29}{21}\)

c) \(0,25+\frac{3}{5}-\left(\frac{1}{8}-\frac{2}{5}+1\frac{1}{4}\right)+\left|\frac{3}{5}\right|\)

\(=\frac{1}{4}+\frac{3}{5}-\frac{1}{8}+\frac{2}{5}-1-\frac{1}{4}+\frac{3}{5}\)

\(=\left(\frac{1}{4}-\frac{1}{4}\right)+\left(\frac{3}{5}+\frac{2}{5}-1\right)+\frac{3}{5}-\frac{1}{8}=\frac{19}{40}\)

2) \(-\frac{3}{5}-x=0,75\)

=> \(-\frac{3}{5}-x=\frac{3}{4}\)

=> \(x=-\frac{3}{5}-\frac{3}{4}=\frac{-27}{20}\)

b) \(x+\frac{1}{3}=\frac{2}{5}-\left(-\frac{1}{3}\right)\)

=> \(x+\frac{1}{3}=\frac{2}{5}+\frac{1}{3}\)

=> \(x=\frac{2}{5}\)

c) |2x - 4| + 1 = 5

=> |2x - 4| = 4

<=> \(\orbr{\begin{cases}2x-4=4\\2x-4=-4\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=4\\x=0\end{cases}}\)

Giúp mình với nha cả nhả :<

Cả nhà làm vài ý thui cx được ạ :<

Bài 2 :

\(a,\frac{3}{2}.\frac{4}{9}-\frac{1}{5}+\frac{2}{15}\)

\(=\frac{2}{3}-\frac{1}{5}+\frac{2}{15}\)

\(=\frac{10}{15}-\frac{3}{15}+\frac{2}{15}\)

\(=\frac{9}{15}=\frac{3}{5}\)

\(b,\left(\frac{1}{2}\right)^2.\frac{4}{3}+\frac{8}{5}:\frac{2}{5}\)

\(=\frac{1}{4}.\frac{4}{3}+\frac{8}{5}.\frac{5}{2}\)

\(=\frac{1}{3}+4\)

\(=\frac{13}{3}\)

\(c,\sqrt{196}-\sqrt{100}+\sqrt{\frac{9}{4}}\)

\(=14-10+\frac{3}{2}\)

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

\(=\frac{11}{2}\)

Học tốt

Bài 1

\(a,\left(\frac{3}{5}\right)^2-\left[\frac{1}{3}:3-\sqrt{16}.\left(\frac{1}{2}\right)^2\right]-\left(10.12-2014\right)^0\)

\(=\frac{9}{25}-\left[\frac{1}{9}-4.\frac{1}{4}\right]-1\)

\(=\frac{9}{25}-\left(-\frac{8}{9}\right)-1\)

\(=\frac{9}{25}+\frac{8}{9}-1\)

\(=\frac{56}{225}\)

\(b,|-\frac{100}{123}|:\left(\frac{3}{4}+\frac{7}{12}\right)+\frac{23}{123}:\left(\frac{9}{5}-\frac{7}{15}\right)\)

\(=\frac{100}{123}:\left(\frac{4}{3}\right)+\frac{23}{123}:\frac{4}{3}\)

\(=\left(\frac{100}{123}+\frac{23}{123}\right):\frac{4}{3}\)

\(=1:\frac{4}{3}=\frac{3}{4}\)

Phần c đăng riêng vì mk chưa tìm đc cách giải bt mỗi đáp án :v 

\(c,\frac{\left(-5\right)^{32}.20^{43}}{\left(-8\right)^{29}.125^{25}}\)

\(=\frac{\left(-5\right)^{32}.\left(4.5\right)^{43}}{\left[4.\left(-2\right)\right]^{29}.\left(-5^3\right)^{25}}\)

\(=\frac{-5^{32}.4^{43}.5^{43}}{4^{29}.\left(-2\right)^{29}.\left(5\right)^{75}}\)

\(=\frac{\left(-5^4\right)^8.4^{43}.5^{43}}{4^{29}.\left(-2\right)^{29}.\left(5^3\right)^{25}}\)

\(=-\frac{1}{2}\)

28 tháng 7 2016

\(\left(\sqrt{4,5}-\frac{1}{2}.\sqrt{72}+5\sqrt{\frac{1}{2}}\right).\left(42\sqrt{\frac{25}{6}}-10\sqrt{\frac{3}{2}}-12\sqrt{\frac{98}{3}}\right)\)

=\(\left(\frac{3\sqrt{2}}{2}-3\sqrt{2}+\frac{5\sqrt{2}}{2}\right).\left(35\sqrt{6}-5\sqrt{6}-28\sqrt{6}\right)\)

=\(\left(\frac{3\sqrt{2}-6\sqrt{2}+5\sqrt{2}}{2}\right).2\sqrt{6}\)

=\(2\sqrt{2}.\sqrt{6}=4\sqrt{3}\)