3x - 6 = 5x + 2

=> 3x = 5x + 8

=> 3x - 5x = 8

=> -2x = 8

=> x = -4

\(3x-6=5x+2\)

\(\Rightarrow3x-5x=2+6\)

\(\Rightarrow-2x=8\)

\(\Rightarrow x=-4\)

3x - 6 = 5x + 2

=> 3x - 6 - 5x - 2 = 0 ( chuyển vế thì đổi dấu )

=> -2x - 8 = 0

=> -2x = 8

=> x = -4

\(\dfrac{3}{x}=\dfrac{1}{y}=\dfrac{6}{2}\)

\(\Rightarrow\dfrac{3}{x}=\dfrac{1}{y}=3\)

\(\Rightarrow\left\{{}\begin{matrix}x=1\\y=\dfrac{1}{3}\end{matrix}\right.\)

x = 1

y = 1/3

x = 1 

y = 1/3. 

a: \(\Rightarrow10x^2+9x-\left(10x^2+15x-2x-3\right)=8\)

\(\Leftrightarrow10x^2+9x-10x^2-13x+3=8\)

=>-4x=5

hay x=-5/4

b: \(\Leftrightarrow21x-15x^2-35+25x+15x^2-10x+6x-4-2=0\)

=>42x=41

hay x=41/42

`a)(10x+9)x-(5x-1)(2x+3)=8`

`<=>10x^2+9x-10x^2-15x+2x+3=8`

`<=>-4x=5`

`<=>x=-5/4`     Vậy `S={-5/4}`

`b)(3x-5)(7-5x)+(5x+2)(3x-2)-2=0`

`<=>21x-15x^2-35+25x+15x^2-10x+6x-4-2=0`

`<=>42x=41`

`<=>x=41/42`       Vậy `S={41/42}`

a: 

=>-4x=5

hay x=-5/4

b: 

=>42x=41

hay x=41/42

Anh ko ghi lại đề nha em ! 

\(\Leftrightarrow\orbr{\begin{cases}x^2+1=0\\3x^2-5x+2=0\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x^2=-1\left(vn\right)\\x_1=1;x_2=\frac{2}{3}\end{cases}}\)( vn là vô nghiệm nha )

Vậy : x = 1 hoặc x = 2/3 

\(\left(x^2+1\right).\left(3x^2-5x+2\right)=0\)

\(x^2\ge0\Rightarrow x^2+1\ge1\)

\(\RightarrowĐể\left(x^2+1\right).\left(3x^2-5x+2\right)=0\)

\(\Rightarrow3x^2-5x+2=0\Rightarrow3x^2-3x-2x+2=0\)

\(\Rightarrow3x.\left(x-1\right)-2.\left(x-1\right)=0\Rightarrow\left(3x-2\right).\left(x-1\right)=0\Rightarrow\orbr{\begin{cases}x=1\\x=\frac{2}{3}\end{cases}}\)

a)(3x-1)(2x+7)-(x+1)(6x-5)=16

=6x^2+21x-2x-7-(6x^2-5x+6x-5)=16

=6x^2+21x-2x-7-6x^2+5x-6x+5=16

=18x-2=16

18x=16+2

18x=18

x=1

​vậy x=1

b)(10x+9)x-(5x-1)(2x+3)=8

10x^2+9x-(10x^2+15x-2x-3)=8

10x^2+9x-10x^2-15x+2x+3=8

-4x+3=8

-4x=8-3

-4x=5

x=-5/4.

vay x=-5/4

Chọn A