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a) (-7+-5) = -12

b) (-12+-29) = -41

9 tháng 2 2020

a) (-7) + (-5) = -( 7 + 5) = -12

b) (-12) + (-29) = -( 12 + 29) = -41

15 tháng 4 2019

\(\left(19\frac{5}{8}:\frac{7}{12}-13\frac{1}{4}:\frac{7}{12}\right).\frac{4}{5}\)

\(=\left(\frac{157}{8}:\frac{7}{12}-\frac{53}{4}:\frac{7}{12}\right).\frac{4}{5}\)

\(=\left[\left(\frac{157}{8}-\frac{53}{4}\right):\frac{7}{12}\right].\frac{4}{5}\)

\(=\left[\frac{51}{8}:\frac{7}{12}\right].\frac{4}{5}\)

\(=\frac{153}{14}.\frac{4}{5}\)

\(=\frac{306}{35}\)

15 tháng 4 2019

\(\left(\frac{-2}{5}+\frac{3}{7}\right)-\left(\frac{4}{9}+\frac{12}{20}-\frac{13}{35}\right)+\frac{7}{35}\)

\(=\frac{1}{35}-\frac{212}{315}+\frac{7}{35}\)

\(=\frac{1}{35}+\frac{-212}{315}+\frac{7}{35}\)

\(=\frac{9}{315}+\frac{-212}{315}+\frac{63}{315}\)

\(=\frac{-140}{315}=\frac{-4}{9}\)

16 tháng 3 2018

a )   ( -1/6 + 5/12 ) + 7/12

= -1/6 + ( 5/12 + 7/12 ) 

= -1/6 + 12/12

= -2/12 + 12/12 

=        -10/12

=        -5/6

11 tháng 4 2019

\(a,0,5x-\frac{2}{3}x=\frac{7}{12}\Rightarrow\frac{1}{2}x-\frac{2}{3}x=\frac{7}{12}\)

\(\Rightarrow x\left(\frac{1}{2}-\frac{2}{3}\right)=\frac{7}{12}\Rightarrow x\cdot\left(\frac{3}{6}-\frac{4}{6}\right)=\frac{7}{12}\)

\(\Rightarrow x\cdot\left(-1\right)=\frac{7}{12}\Rightarrow x=\frac{7}{12}:\left(-1\right)=\frac{7}{-12}\)

\(c,\frac{\left(x-5\right)}{12}\cdot\frac{9}{29}=\frac{-6}{29}\Rightarrow\frac{\left(x-5\right)}{12}=\frac{-6}{29}:\frac{9}{26}\)

\(\frac{\Rightarrow\left(x-5\right)}{12}=\frac{-6}{9}=\frac{-2}{3}\Rightarrow x-5=-\frac{2}{3}\cdot12\)

\(\Rightarrow x-5=\frac{-24}{3}=-8\Rightarrow x=-8+5=-3\)

11 tháng 4 2019

\(a,0,5x-\frac{2}{3}x=\frac{7}{12}\)

\(\Rightarrow\frac{1}{2}x-\frac{2}{3}x=\frac{7}{12}\)

\(\Rightarrow-\frac{1}{6}x=\frac{7}{12}\)

\(\Rightarrow x=-\frac{7}{2}\)

\(c,\frac{x-5}{12}\cdot\frac{9}{29}=-\frac{6}{29}\)

\(\Rightarrow\frac{x-5}{12}=-\frac{2}{3}\)

\(\Rightarrow x-5=12.\left(-\frac{2}{3}\right)\)

\(\Rightarrow x-5=-8\)

\(\Rightarrow x=-3\)

3 tháng 2 2017

a) \(12x-60+21-7x-5=0\)

\(\Rightarrow5x-44=0\)

\(\Rightarrow5x=44\)

\(\Rightarrow x=\frac{44}{5}\)

Vậy: \(x=\frac{44}{5}\)

3 tháng 2 2017

b) \(2x^2-3=29\)

\(\Rightarrow2x^2=3+29=32\)

\(\Rightarrow x^2=\frac{32}{2}=16\)

\(\Rightarrow x=\sqrt{16}=4\)

Vậy: \(x=4\)

27 tháng 4 2017

x-7=15-(-21)

x-7=36

x=36-7

x=29

27 tháng 4 2017

x = 29 đấy bạn

k cho mình nha

16 tháng 2 2022

a)P=\(\dfrac{-2}{7}+\dfrac{14}{29}+\dfrac{12}{33}+\dfrac{15}{29}+\dfrac{21}{33}+\dfrac{2}{7}\)

      =\(\left(\dfrac{-2}{7}+\dfrac{2}{7}\right)+\left(\dfrac{14}{29}+\dfrac{15}{29}\right)+\left(\dfrac{12}{33}+\dfrac{21}{33}\right)\)

      =0+1+1=2

b)\(\dfrac{2}{7}.\dfrac{5}{19}+\dfrac{2}{7}.\dfrac{14}{19}+\dfrac{21}{19}-\dfrac{2}{7}.\dfrac{1}{5}\)

=\(\dfrac{2}{7}.\left(\dfrac{5}{19}+\dfrac{14}{19}-\dfrac{1}{5}\right)+\dfrac{21}{19}\)

=\(\dfrac{2}{7}.\dfrac{4}{5}+\dfrac{21}{19}=\dfrac{887}{665}\)

31 tháng 7 2023

a) \(\left(x+5\right).6-7=29\)

\(\Rightarrow\left(x+5\right).6=29+7\)

\(\Rightarrow\left(x+5\right).6=36\)

\(\Rightarrow\left(x+5\right)=36:6=6\)

\(\Rightarrow x=6-5=1\)

b) \(5x-3x=12-3.2\)

\(\Rightarrow2x=6\Rightarrow x=6:2=3\)

c) \(\dfrac{1}{4}.3< x< \dfrac{51}{50}.4\)

\(\Rightarrow\dfrac{3}{4}< x< \dfrac{102}{25}\)

6 tháng 2 2022

\(a,-35.12-8.35\)

\(=\left(-35\right)\left(12+8\right)\)

\(=-700\)

\(b,-23.7-7.59-18.7\)

\(=7\left(-23-59-18\right)\)

\(7.\left(-100\right)=-700\)

\(b,115-\left(-12+29\right)\)

\(=115+12-29\)

\(=98\)

\(c,3.\left(-7\right)^2+5.\left(-4\right)^3\)

\(=3.49-5.64\)

\(=147-320\)

\(=-173\)

6 tháng 2 2022

a)-35.12-8-35=-35(12+8)=-35.20=-700

b)23.(-7)-7.5+(-18).7=-7(23+59+18)=-7.100=-700

c)115-(-12+29)=115+12-29=98

d)\(3\left(-7\right)^2+5\left(-4\right)^3=3.7^2-5.4^3=3.49-5.64=147-320-173\)