a)\(x-15\%x=\frac{1}{3}\)

\(x.\left(1-15\%\right)=\frac{1}{3}\)

\(x.\frac{-280}{3}=\frac{1}{3}\)

\(x=\frac{1}{3}:\frac{-280}{3}\)

\(x=\frac{-1}{280}\)

Vậy \(x=\frac{-1}{280}\)

b)\(\frac{4}{5}x-x-\frac{3}{2}x+\frac{6}{5}=\frac{1}{2}-\frac{4}{3}\)

\(-\frac{17}{10}x+\frac{6}{5}=\frac{-5}{6}\)

\(-\frac{17}{10}x=-\frac{5}{6}-\frac{6}{5}\)

\(-\frac{17}{10}x=\frac{-61}{30}\)

\(x=\frac{-61}{30}:\frac{-17}{10}\)

\(x=\frac{61}{51}\)

Vậy \(x=\frac{61}{51}\)

21/5 + 3:|x/4-2/3|=6

=>3:|x/4-2/3|=6-21/5

=>|x/4-2/3|=3:9/5=5/3

ta có 2 th

TH₁ x/4-2/3=5/3

=>x/4=2 =>x=8

TH₂ x/4-2/3=-5/3

=>x/4=-1 =>x=-4

vậy x thuộc {-4;8}

nhớ cho mik

Bạn ơi, cho mk hỏi:

Tại sao lại từ   x/4 - 2/3 = 5/3 lại suy ra x/4 = 2. 

\(\frac{21}{5}+3\div\left|\frac{x}{4}-\frac{2}{3}\right|=6\)

\(\Rightarrow3\div\left|\frac{x}{4}-\frac{2}{3}\right|=6-\frac{21}{5}\)

\(\Rightarrow3\div\left|\frac{x}{4}-\frac{2}{3}\right|=\frac{9}{5}\)

\(\Rightarrow\left|\frac{x}{4}-\frac{2}{3}\right|=3\div\frac{9}{5}\)

\(\Rightarrow\left|\frac{x}{4}-\frac{2}{3}\right|=\frac{5}{3}\)

\(\Rightarrow\orbr{\begin{cases}\frac{x}{4}-\frac{2}{3}=\frac{5}{3}\\\frac{x}{4}-\frac{2}{3}=\frac{-5}{3}\end{cases}\Rightarrow\orbr{\begin{cases}\frac{x}{4}=\frac{5}{3}+\frac{2}{3}\\\frac{x}{4}=\frac{-5}{3}+\frac{2}{3}\end{cases}}}\)

\(\Rightarrow\orbr{\begin{cases}\frac{x}{4}=\frac{7}{3}\\\frac{x}{4}=-1\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{7}{3}.4\\x=-1.4\end{cases}\Rightarrow}\orbr{\begin{cases}x=\frac{28}{3}\\x=-4\end{cases}}}\)

Vậy \(x=\frac{28}{3}\) hoặc \(x=-4\)

A) \(X+15=4^2\)

=>  \(X=16-15\)

=>  \(X=1\)

b)  100 : ( 35 - X ) = 5

=>   35 - X = 100 : 5

=>  35 - X  = 20

=>   X =  35 -  20

=>  X =  15 

C) \(3X-17=2^2\cdot2^4\)

=> \(3X-17=2^6=64\)

=>  \(3X=64+17\)

=>  \(3X=81\)

=>   \(X=27\)

d) 120  -  20 ( 50 - 4X )  = 0

=>  20 ( 50 - 4X )   =  120

=>   50 - 4X  = 120 : 20

=>   50 - 4X  =  6

=>  4X  =  50 -   6

=>   4X  =  44

=>  X  = 11

Ko cần biet vi ko biet ang ang

\(\dfrac{1}{2022}\) \(\times\) \(\dfrac{2}{5}\) + \(\dfrac{1}{2022}\) \(\times\) \(\dfrac{7}{5}\) - \(\dfrac{1}{2022}\) \(\times\) \(\dfrac{8}{10}\)

= \(\dfrac{1}{2022}\) \(\times\) ( \(\dfrac{2}{5}\) + \(\dfrac{7}{5}\) - \(\dfrac{8}{10}\))

= \(\dfrac{1}{2022}\) \(\times\) ( \(\dfrac{9}{5}\) - \(\dfrac{4}{5}\))

= \(\dfrac{1}{2022}\) \(\times\) \(\dfrac{5}{5}\)

=  \(\dfrac{1}{2022}\times1\)

= \(\dfrac{1}{2022}\)

b: \(8x-\dfrac{1}{\sqrt{2+x}}+5\)

a. -> \(3x^2-\dfrac{1}{\sqrt{5}}.\left(x-m\right)-15=3\)

\(3\sqrt{x}-2x=0\)

\(\Leftrightarrow3\sqrt{x}=2x\)

\(\Leftrightarrow\sqrt{x}=\frac{2x}{3}\)

\(\Leftrightarrow\left(\sqrt{x}\right)^2=\frac{4x^2}{9}\)

\(\Leftrightarrow x=\frac{4x^2}{9}\)

\(\Leftrightarrow\frac{4x^2}{x}=9\)

\(\Leftrightarrow4x=9\)

\(\Leftrightarrow x=\frac{9}{4}\)

\(3\sqrt{x}-2x=0\)

\(\Leftrightarrow9x-4x^2=0\)

\(\Leftrightarrow x\left(9-4x\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x=0\\9-4x=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=0\\x=\frac{9}{4}\end{cases}}}\)

Từ biểu thức, ta suy ra:

-12x+60+21-7x=5

<=>81-19x=5

<=>81-19x-5=0

<=>76-19x=0

<=>19x=76

<=>x=4

Vậy x=4

  -12 ( x-5 ) + 7 ( 3 - x ) = 5 

=> -12x + 60 + 21 - 7x = 5

=> -19x = 5 - 81

=> -19x = -76

=> x = 4

cảm ơn các bạn nha

\((6-4\frac{1}{2}):0,03+(3\frac{1}{20}-2,65):4+\frac{2}{5}\)

\((6-4,5):0,03+(3,05-2,65):4+0,4\)

\(=1,5:0,03+0,4:4+0,4\)

\(=50+(0,4\cdot2):4\)

\(=50+0,2\)

\(=50,2\)

Chúc bạn học tốt