\(\frac{3\frac{1}{3}}{2\frac{5}{6}}=\frac{x}{0,81}\)

làm giúp mk vs ạ

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9 tháng 8 2020

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

\(\Leftrightarrow\frac{x-1}{1}+\frac{x-1}{2}-\frac{x-1}{3}-\frac{x-1}{4}-\frac{x-1}{5}=0\)

\(\Leftrightarrow\left(x-1\right)\left(\frac{1}{1}+\frac{1}{2}-\frac{1}{3}-\frac{1}{4}-\frac{1}{5}\right)=0\)

Vì \(\frac{1}{1}+\frac{1}{2}-\frac{1}{3}-\frac{1}{4}-\frac{1}{5}\ne0\)

\(\Rightarrow x-1=0\)

\(\Rightarrow x=1\)

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

\(\Leftrightarrow\frac{x-1}{1}+\frac{x-1}{2}-\frac{x-1}{3}-\frac{x-1}{4}-\frac{x-1}{5}=0\)

\(\Leftrightarrow\left(x-1\right)\left(1+\frac{1}{2}-\frac{1}{3}-\frac{1}{4}-\frac{1}{5}\ne0\right)=0\)

\(\Leftrightarrow x=1\)

9 tháng 9 2018

a)\(\frac{x+3}{x+5}=7\Leftrightarrow x+3=7\left(x+5\right)\)

\(\Leftrightarrow x+3=7x+35\)

\(\Leftrightarrow-6x=32\)

\(\Leftrightarrow x=-\frac{16}{3}\)

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

\(\Leftrightarrow3\left(2x-1\right)=-2\left(3x+5\right)\)

\(\Leftrightarrow6x-3=-6x-10\)

\(\Leftrightarrow12x=-7\)

\(\Leftrightarrow x=-\frac{7}{12}\)

9 tháng 9 2018

c)\(\frac{x+1}{4}=\frac{9}{x+1}\Leftrightarrow\left(x+1\right)^2=36\)

\(\Leftrightarrow\left(x+1\right)^2=6^2\)

\(\Leftrightarrow\orbr{\begin{cases}x+1=6\\x+1=-6\end{cases}\Leftrightarrow\orbr{\begin{cases}x=5\\x=-7\end{cases}}}\)

d)\(\frac{6x-1}{2x+3}=\frac{3x}{x+2}\)

\(\Leftrightarrow\left(6x-1\right)\left(x+2\right)=3x\left(2x+3\right)\)

\(\Leftrightarrow6x^2+12x-x-2=6x^2+9x\)

\(\Leftrightarrow2x=2\Leftrightarrow x=1\)

\(\frac{x-1}{1}+\frac{x-1}{2}=\frac{x}{3}+\frac{x}{4}-\frac{7}{12}\)

\(\Leftrightarrow\frac{12x-12}{12}+\frac{6x-6}{12}=\frac{4x}{12}+\frac{3x}{12}-\frac{7}{12}\)

Khử mẫu : \(12x-12+6x-6=4x+3x-7\)

\(\Leftrightarrow18x-18=7x-7\Leftrightarrow11x=11\Leftrightarrow x=1\)

9 tháng 8 2020

\(\frac{x-1}{1}+\frac{x-1}{2}=\frac{x}{3}+\frac{x}{4}-\frac{7}{12}\)

\(\Leftrightarrow\frac{12x-12}{12}+\frac{6x-6}{12}=\frac{4x}{12}+\frac{3x}{12}-\frac{7}{12}\)

\(\Leftrightarrow\frac{12x-12+6x-6}{12}=\frac{4x+3x-7}{12}\)

\(\Leftrightarrow18x-18=7x-7\)

\(\Leftrightarrow18x+7x=18+7\)

\(\Leftrightarrow25x=25\)

\(\Leftrightarrow x=1\)

20 tháng 12 2018

a) \(\frac{1}{4}+\frac{1}{3}:2x=-5\)

\(\frac{1}{3}:2x=\frac{-21}{4}\)

\(2x=\frac{-4}{63}\)

\(x=\frac{2}{63}\)

20 tháng 12 2018

b) \(\left(3x-\frac{1}{4}\right)\left(x+\frac{1}{2}\right)=0\)

\(\Rightarrow\orbr{\begin{cases}3x-\frac{1}{4}=0\\x+\frac{1}{2}=0\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=\frac{1}{12}\\x=\frac{-1}{2}\end{cases}}\)

Vậy.........

7 tháng 9 2016

 a.x+30/100x=-1,1

13/10x=-1,1

x=-11/13

b. (x-1/2):1/3 +5/7=9/5/7

(x-1/2):1/3=9

x-1/2=3

x=7/2

c. -5/6-x=7/12-1/3

x=-5/6-7/12-1/3

x=-7/4

d. 3(x+3)=-15

x+3=-5

x=-8

e. (4,5-2x)(-11/7)=11/14

4,5-2x=11/14:-11/7

4,5-2x=-1/2

2x=4,5+1/2

2x=5

x=5/2