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23 tháng 2 2021

mik ko hieu lam

28 tháng 5 2020

a) \(\frac{5}{6}-\left|1-x\right|=\frac{1}{2}\)

<=> \(\left|1-x\right|=\frac{5}{6}-\frac{1}{2}\)

<=>\(\left|1-x\right|=\frac{1}{3}\)

<=>\(\orbr{\begin{cases}1-x=\frac{1}{3}\\1-x=-\frac{1}{3}\end{cases}}\)

<=>\(\orbr{\begin{cases}x=1-\frac{1}{3}\\x=1-\left(-\frac{1}{3}\right)\end{cases}}\)

<=>\(\orbr{\begin{cases}x=\frac{2}{3}\\x=\frac{4}{3}\end{cases}}\)

Vậy \(x=\frac{2}{3}\)hoặc\(x=\frac{4}{3}\)

b) \(\frac{8^5.\left(-5\right)^8+\left(-2\right)^5.\left(-10\right)^9}{4^{10}.5^7+20^8.4}.\frac{144}{25}\)

\(=\frac{2^{15}.5^8+2^5.2^9.5^9}{2^{20}.5^7+2^{16}.5^8.2^2}.\frac{2^4.3^2}{5^2}\)

\(=\frac{2^{14}.5^8.\left(2+5\right)}{2^{18}.5^7.\left(2^2+5\right)}.\frac{2^4.3^2}{5^2}\)

\(=\frac{2^{14}.5^8.7}{2^{18}.5^7.3^2}.\frac{2^4.3^2}{5^2}\)

\(=\frac{2^{18}.3^2.5^8.7}{2^{18}.3^2.5^9}\)

\(=\frac{7}{5}\)

Học tốt!!!!

28 tháng 5 2020

a.\(\frac{5}{6}-\left|1-x\right|=\frac{1}{2}\)

\(=>\left|1-x\right|=\frac{5}{6}-\frac{1}{2}\)

\(=>\left|1-x\right|=\frac{1}{3}\)

\(=>\orbr{\begin{cases}1-x=\frac{1}{3}\\1-x=\frac{-1}{3}\end{cases}}\)

\(=>\orbr{\begin{cases}x=1-\frac{1}{3}=\frac{2}{3}\\x=1-\frac{-1}{3}=\frac{4}{3}\end{cases}}\)

5 tháng 2 2017

a)210-475-100+670

=(-365)+670

=305

b)114-(-6)+7-20

=114+6+7-20

=120+7-20

=120-20+7

=100+7

=107

c)215+[144-(144+215)]

=215+[144-144-215]

=215+[0-215]

=215+(-215)

=0

d) (-20).17-45.83

=(-340)-3735

=(-4075)

30 tháng 10 2019

a) x = 34             

b) x= 5                

c) x = 35              

d) x = 0

e) x = 410            

f) x= 170

6 tháng 12 2018

A.( 13 + 25 ) + ( 24 - 13 - 42 - 25 )

= 13 + 25 + 24 - 13 - 42 - 25

= ( 13 - 13 ) + ( 25 - 25 ) + ( 24 - 42 )

= 0 + 0 + ( - 18 )

= -18

B. ( 215 - 34 + 127 ) - ( 315 - 144 - 227 )

= 215 - 34 + 127 - 315 + 144 + 227

= ( 215 - 315 ) + ( 144 - 34 ) + ( 127 + 227 )

= - 100 + 110 + 354

= 10 + 354

= 364

Bài 1:

a) Ta có: \(\frac{8}{40}+\frac{-4}{20}-\frac{3}{5}\)

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

\(=\frac{-3}{5}\)

b) Ta có: \(\frac{-7}{12}+\frac{-2}{12}-\frac{-3}{36}\)

\(=\frac{-7}{12}+\frac{-2}{12}-\frac{-1}{12}\)

\(=\frac{-9+1}{12}=\frac{-8}{12}=\frac{-2}{3}\)

c) Ta có: \(\left(\frac{1}{6}+\frac{-4}{13}\right)-\left(-\frac{17}{6}-\frac{30}{13}\right)\)

\(=\frac{1}{6}+\frac{-4}{13}+\frac{17}{6}+\frac{30}{13}\)

\(=3+2=5\)

d) Ta có: \(-\frac{-5}{4}+\frac{7}{4}-\frac{-11}{7}+\frac{2}{7}\)

\(=\frac{5}{4}+\frac{7}{4}+\frac{11}{7}+\frac{2}{7}\)

\(=3+\frac{13}{7}=\frac{21}{7}+\frac{13}{7}=\frac{34}{7}\)

e) Ta có: \(-\frac{1}{8}+\frac{-7}{9}+\frac{-7}{8}+\frac{6}{7}+\frac{2}{14}\)

\(=-1+1+\frac{-7}{9}\)

\(=-\frac{7}{9}\)

f) Ta có: \(\frac{-2}{9}-\frac{11}{-9}+\frac{5}{7}-\frac{-6}{-7}\)

\(=\frac{-2-\left(-11\right)}{9}+\frac{5-6}{7}\)

\(=1+\frac{-1}{7}=\frac{7}{7}+\frac{-1}{7}=\frac{6}{7}\)