-2x - 11 = 3x +2

-2x -11 - 2 = 3x

-2x - 13 = 3x

2x + 13 = 3x

13 = x

bài này yêu cầu tìm x thuộc Z nha mấy bn.

\(-2x-11⋮3x+2\)

=>\(-\frac{2}{3}\left(3x+2\right)+\frac{4}{3}⋮3x+2\)

=>\(3\left(-\frac{2}{3}\left(3x+2\right)+\frac{4}{3}\right)⋮3x+2\)

=>\(-2\left(3x+2\right)+4⋮3x+2\)

=>\(4⋮3x+2\)

=>\(3x+2\inƯ\left(4\right)=\left\{\pm1\pm2\pm4\right\}\)

tự làm nốt nha

\(120.450:120\)

\(=\left(120:120\right).450\)

\(=1.450\)

\(=450\)

120 . 450 : 120

= ( 120 : 120 ) .450

= 1 .450

=450

120 . 450 : 120 

= 450. ( 120 : 120 ) = 450

*Sxl

Trả lời:

\(\left(\frac{2}{3}x-\frac{4}{9}\right).\left[\frac{1}{2}+\left(-\frac{3}{7}\right)\div x\right]=0\)

\(\Leftrightarrow\orbr{\begin{cases}\frac{2}{3}x-\frac{4}{9}=0\\\frac{1}{2}+\left(-\frac{3}{7}\right)\div x=0\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}\frac{2}{3}x=\frac{4}{9}\\\frac{-3}{7}\div x=\frac{-1}{2}\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=\frac{2}{3}\\x=\frac{6}{7}\end{cases}}\)

Vậy \(x\in\left\{\frac{2}{5},\frac{6}{7}\right\}\)

Học tốt nhé 

Trả lời :

\(\left(\frac{2}{3}x-\frac{4}{9}\right)\times\left(\frac{1}{2}-\frac{3}{7}\div x\right)=0\)

\(\Rightarrow\orbr{\begin{cases}\frac{2}{3}x-\frac{4}{9}=0\\\frac{1}{2}-\frac{3}{7}\div x=0\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}\frac{2}{3}x=\frac{4}{9}\\\frac{3}{7}\div x=\frac{1}{2}\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=\frac{2}{3}\\x=\frac{6}{7}\end{cases}}\)

Cảm ơn các bn nhé ....thank you very much...

Ta có:  \(\hept{\begin{cases}\left|x-6\right|\ge0\forall x\\\left|y-3\right|\ge0\forall y\end{cases}}\)

Mà \(\left|x-6\right|+\left|y-3\right|=0\)

\(\Rightarrow\hept{\begin{cases}\left|x-6\right|=0\\\left|y-3\right|=0\end{cases}\Rightarrow\hept{\begin{cases}x-6=0\\y-3=0\end{cases}\Rightarrow}\hept{\begin{cases}x=6\\y=3\end{cases}}}\)

vậy....

hok tốt!!

cccccccccccccccc

bn ơi trên kia kìa mà thôi 

10^2+12^2+14^2+....+100^ 2

9^2+11^2+13^2+....+99^2

E.bai tap thay tao ma giam hoi a

a, 3x³ . 5x² = 15x⁵

b, 2x . ( 3x² + 2x ) = 6x³ + 4x²

c, -3xy . ( 2x + 5y ) = -6x²y +-15xy²

d, 3x². ( 6 - x² + 2x ) = 18x² - 3x³ + 6x³

e, ( x + 2 ) . ( x + 3 ) = x² + 5x + 6

i,  ( x - 4 ) . ( x + 4 ) = x² - 16

h, ( 1 - 2x ) . ( 3x + 2 ) = 2 - 6x² - x

k, ( x - y ) . ( x + y ) = x² - y²

t, ( 2x + 1 ) . ( 4x² - 2x + 1 ) = 8x³ - 1 

a, 3x³ . 5x² = 15x⁵

b, 2x . ( 3x² + 2x ) = 6x³ + 4x²

c, -3xy . ( 2x + 5y ) = -6x²y +-15xy²

d, 3x². ( 6 - x² + 2x ) = 18x² - 3x³ + 6x³

e, ( x + 2 ) . ( x + 3 ) = x² + 5x + 6

i,  ( x - 4 ) . ( x + 4 ) = x² - 16

h, ( 1 - 2x ) . ( 3x + 2 ) = 2 - 6x² - x

k, ( x - y ) . ( x + y ) = x² - y²

t, ( 2x + 1 ) . ( 4x² - 2x + 1 ) = 8x³ - 1 

 là 3 nếu X là 2018