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15 tháng 12 2023

a,     (\(\dfrac{9}{10}\) - \(\dfrac{15}{16}\)\(\times\) ( \(\dfrac{5}{12}\) - \(\dfrac{11}{15}\) - \(\dfrac{7}{20}\))

=  (\(\dfrac{72}{80}\) - \(\dfrac{75}{80}\))  \(\times\) (\(\)\(\dfrac{25}{60}\) - \(\dfrac{44}{60}\)  - \(\dfrac{21}{60}\))

= - \(\dfrac{3}{80}\)  \(\times\) (- \(\dfrac{2}{3}\))

\(\dfrac{1}{40}\) 

15 tháng 12 2023

b, (-1)3 + (- \(\dfrac{2}{3}\))2 : 2\(\dfrac{2}{3}\) + \(\dfrac{5}{6}\)

=  -13 +   \(\dfrac{4}{9}\) : \(\dfrac{8}{3}\) + \(\dfrac{5}{6}\)

= -1 + \(\dfrac{4}{9}\) \(\times\) \(\dfrac{3}{8}\) + \(\dfrac{5}{6}\)

= -1 + \(\dfrac{1}{6}\) + \(\dfrac{5}{6}\)
= -1 + 1

= 0

9 tháng 7 2016

a. 2(x-1) + (x+2) - (x+3) = 15 - (x+1)

=>2x-2+x+2-x-3=15-x-1

=>(2x+x-x)-2+2-3=15-1-x

=>2x-3=14-x

=>3x=17

=>x=17/3

b. x+1/15 + x+2/14 = x+4/12 + x+5/11

\(\Rightarrow\frac{x+1}{15}+1+\frac{x+2}{14}+1=\frac{x+4}{12}+1+\frac{x+5}{11}+1\)

\(\Rightarrow\frac{x+16}{15}+\frac{x+16}{14}=\frac{x+16}{12}+\frac{x+16}{11}\)

\(\Rightarrow\frac{x+16}{15}+\frac{x+16}{14}-\frac{x+16}{12}-\frac{x+16}{11}=0\)

\(\Rightarrow\left(x+16\right)\left(\frac{1}{15}+\frac{1}{14}-\frac{1}{12}-\frac{1}{11}\right)=0\)

\(\Rightarrow x+16=0\).Do \(\frac{1}{15}+\frac{1}{14}-\frac{1}{12}-\frac{1}{11}\ne0\)

=>x=-16

16 tháng 5 2022

a.-1,75-(-\(\dfrac{1}{9}\)-2\(\dfrac{1}{8}\))
-1,75-\(\dfrac{1}{9}+\dfrac{17}{8}\)
\(-\dfrac{7}{4}-\dfrac{1}{9}+\dfrac{17}{8}\)
\(\dfrac{-126}{72}-\dfrac{8}{72}+\dfrac{153}{72}\)
=\(\dfrac{19}{72}\)

16 tháng 5 2022

b.\(\dfrac{-1}{12}-\left(2\dfrac{5}{8}-\dfrac{1}{3}\right)\)
\(\dfrac{-1}{12}-\left(\dfrac{21}{8}-\dfrac{1}{3}\right)\)
\(\dfrac{-1}{12}-\dfrac{21}{8}+\dfrac{1}{3}\)
\(\dfrac{-2}{24}-\dfrac{63}{24}+\dfrac{64}{24}\)
=\(\dfrac{-1}{24}\)

`#3107`

a)

\(\dfrac{11}{12}-\left(\dfrac{2}{5}+\dfrac{3}{4}x\right)=\dfrac{2}{3}?\\ \Rightarrow\dfrac{2}{5}+\dfrac{3}{4}x=\dfrac{11}{12}-\dfrac{2}{3}\\ \Rightarrow\dfrac{2}{5}+\dfrac{3}{4}x=\dfrac{1}{4}\\ \Rightarrow\dfrac{3}{4}x=\dfrac{1}{4}-\dfrac{2}{5}\\ \Rightarrow\dfrac{3}{4}x=-\dfrac{3}{20}\\ \Rightarrow x=-\dfrac{3}{20}\div\dfrac{3}{4}\\ \Rightarrow x=-\dfrac{1}{5}\)

Vậy, \(x=-\dfrac{1}{5}\)

b)

\(\dfrac{-2}{5}+\dfrac{5}{3}\cdot\left(\dfrac{3}{2}-\dfrac{4}{15}x\right)=\dfrac{-7}{6}\\ \Rightarrow\dfrac{5}{3}\cdot\left(\dfrac{3}{2}-\dfrac{4}{15}x\right)=\dfrac{-7}{6}-\dfrac{-2}{5}\\ \Rightarrow\dfrac{5}{3}\cdot\left(\dfrac{3}{2}-\dfrac{4}{15}x\right)=-\dfrac{23}{30}\\ \Rightarrow\dfrac{3}{2}-\dfrac{4}{15}x=-\dfrac{23}{30}\div\dfrac{5}{3}\\ \Rightarrow\dfrac{3}{2}-\dfrac{4}{15}x=-\dfrac{23}{50}\\ \Rightarrow\dfrac{4}{15}x=\dfrac{3}{2}-\left(-\dfrac{23}{50}\right)\\ \Rightarrow\dfrac{4}{15}x=\dfrac{49}{25}\\ \Rightarrow x=\dfrac{147}{20}\)

Vậy, \(x=\dfrac{147}{20}\)

c)

\(\dfrac{1}{2}+\dfrac{3}{4}x=\dfrac{1}{4}\\ \Rightarrow\dfrac{3}{4}x=\dfrac{1}{4}-\dfrac{1}{2}\\ \Rightarrow\dfrac{3}{4}x=-\dfrac{1}{4}\\ \Rightarrow x=-\dfrac{1}{4}\div\dfrac{3}{4}\\ \Rightarrow x=-\dfrac{1}{3}\)

Vậy, \(x=-\dfrac{1}{3}.\)

\(#Emyeu1aithatroi...\)

29 tháng 9 2023

(2/5 + 3/4 . x)= 11/12 -2/3

(2/5 +3/4 . x)= 1/4

3/4 . x          = 1/4 - 2/5

3/4 . x          = -3/20

x                  = -3/20 : 3/4

x                  = -1/5

Vậy .....

4 tháng 10 2018

x=-36

x=11

x=100

x=14

4 tháng 10 2018

x=-36

x=11

x=100

x=14

16 tháng 2 2020

        \(\frac{x+1}{15}+\frac{x+2}{14}=\frac{x+5}{11}+\frac{x+4}{12}\)
\(\Leftrightarrow\frac{x+1}{15}+\frac{x+2}{14}+2=\frac{x+5}{11}+\frac{x+4}{12}+2\)
\(\Leftrightarrow\left(\frac{x+1}{15}+1\right)+\left(\frac{x+2}{14}+1\right)=\left(\frac{x+5}{11}+1\right)+\left(\frac{x+4}{12}+1\right)\)
\(\Leftrightarrow\frac{x+1+15}{15}+\frac{x+2+14}{14}=\frac{x+5+11}{11}+\frac{x+4+12}{12}\)
\(\Leftrightarrow\frac{x+16}{15}+\frac{x+16}{14}=\frac{x+16}{11}+\frac{x+16}{12}\)
\(\Leftrightarrow\frac{x+16}{15}+\frac{x+16}{14}-\frac{x+16}{11}-\frac{x+16}{12}=0\)
\(\Leftrightarrow\left(x+16\right)\left(\frac{1}{15}+\frac{1}{14}-\frac{1}{11}-\frac{1}{12}\right)=0\)
\(\Leftrightarrow x+16=0\)
\(\Leftrightarrow x=-16\)

\(\frac{x+1}{15}+\frac{x+2}{14}=\frac{x+5}{11}+\frac{x+4}{12}\)

=>\(\frac{x+1}{15}+1+\frac{x+2}{14}+1=\frac{x+5}{11}+1+\frac{x+4}{12}+1\)

=>\(\frac{x+1}{15}+\frac{15}{15}+\frac{x+2}{14}+\frac{14}{14}=\frac{x+5}{11}+\frac{11}{11}+\frac{x+4}{12}+\frac{12}{12}\)

=>\(\frac{x+1+15}{15}+\frac{x+2+14}{14}=\frac{x+5+11}{11}+\frac{x+4+12}{12}\)

=>\(\frac{x+16}{15}+\frac{x+16}{14}=\frac{x+16}{11}+\frac{x+16}{12}\)

=>\(\frac{x+16}{15}+\frac{x+16}{14}-\frac{x+16}{11}-\frac{x+16}{12}\)=0

=>\(\left(x+16\right).\left(\frac{1}{15}+\frac{1}{14}-\frac{1}{11}-\frac{1}{12}\right)=0\)

Mà \(\frac{1}{15}+\frac{1}{14}-\frac{1}{11}-\frac{1}{12}\ne0\)

=>x+16=0

=>x    =0-16

=>x     =-16

Vậy x=-16

Chúc bn học tốt

20 tháng 6 2019

a,\(\frac{11}{12}-\left(\frac{5}{42}-x\right)=\frac{15}{28}-\frac{11}{12}\)

\(\Leftrightarrow\frac{11}{12}-\frac{5}{42}+x=\frac{15}{28}-\frac{11}{12}\)

\(\Leftrightarrow x=\frac{15}{28}-\frac{11}{12}-\frac{11}{12}+\frac{5}{42}\)

\(\Leftrightarrow x=\left(\frac{15}{28}+\frac{5}{42}\right)-\left(\frac{11}{12}+\frac{11}{12}\right)\)

\(\Leftrightarrow x=\frac{55}{84}-\frac{11}{6}\)

\(\Leftrightarrow x=\frac{-33}{28}\)

b, \(\frac{x+1}{10}+\frac{x+1}{11}+\frac{x+1}{12}=\frac{x+1}{13}+\frac{x+1}{14}\)

\(\Leftrightarrow\frac{x+1}{10}+\frac{x+1}{11}+\frac{x+1}{12}-\frac{x+1}{13}-\frac{x+1}{14}=0\)

\(\Leftrightarrow\left(x+1\right)\left(\frac{1}{10}+\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\right)=0\)

\(\Leftrightarrow x+1=0\)

\(\Leftrightarrow x=-1\)