Đáp án + Giải thích các bước giải:

9)

$\frac{1}{3x-2}$ - $\frac{4}{3x+2}$ - $\frac{3x-6}{4-9x^2}$

$\frac{1}{3x-2}$ - $\frac{4}{3x+2}$ + $\frac{3x-6}{9x^2-4}$

$\frac{1}{3x-2}$ - $\frac{4}{3x+2}$ + $\frac{3x-6}{(3x-2)(3x+2)}$

MC: (3x - 2) (3x + 2)

$\frac{1(3x+2)-4(3x-2)+(3x-6)}{(3x-2)(3x+2)}$

$\frac{3x+2-12x+8+3x-6}{(3x-2)(3x+2)}$

$\frac{-6x+4}{(3x-2)(3x+2)}$

$\frac{-2(3x-2)}{(3x-2)(3x+2)}$ = $\frac{-2}{3x+2}$.

10)

$\frac{1}{2x-2y}$ - $\frac{1}{2x+2y}$ + $\frac{y}{y^2-x^2}$

$\frac{1}{2(x-y)}$ - $\frac{1}{2(x+y)}$ - $\frac{y}{x^2-y^2}$

MC: 2 (x - y) (x + y).

$\frac{1(x+y)-1(x-y)-2y}{2(x-y)(x+y)}$ = $\frac{0}{2(x-y)(x+y)}$ = 0.

11)

$\frac{x}{2x-2}$ + $\frac{3x}{2x+2}$ - $\frac{2x^2}{x^2-1}$

$\frac{x}{2(x-1)}$ + $\frac{3x}{2(x+1)}$ - $\frac{2x^2}{(x-1)(x+1)}$

MC: 2 (x - 1) (x + 1).

$\frac{x(x+1)+3x(x-1)-2.2x^2}{2(x-1)(x+1)}$

$\frac{x^2+x+3x^2-3x-4x^2}{2(x-1)(x+1)}$

$\frac{-2x}{2(x-1)(x+1)}$ = $\frac{-x}{x^2-1}$ ($\frac{x}{1-x^2}$).

12)

$\frac{2x+1}{4x-2}$ + $\frac{1-2x}{4x+2}$ - $\frac{2}{1-4x^2}$

$\frac{2x+1}{2(2x-1)}$ + $\frac{1-2x}{2(2x+1)}$ + $\frac{2}{4x^2-1}$

$\frac{2x+1}{2(2x-1)}$ + $\frac{1-2x}{2(2x+1)}$ + $\frac{2}{(2x-1)(2x+1)}$

MC: 2 (2x - 1) (2x + 1).

$\frac{(2x+1)^2+(1-2x)(2x-1)+2.2}{2(2x-1)(2x+1)}$

$\frac{(4x^2+4x+1)-(2x-1)^2+4}{2(2x-1)(2x+1)}$

$\frac{4x^2+4x+1-(4x^2-4x+1)+4}{2(2x-1)(2x+1)}$

$\frac{4x^2+4x+1-(4x^2-4x+1)+4}{2(2x-1)(2x+1)}$

$\frac{8x+4}{2(2x-1)(2x+1)}$ = $\frac{4(2x+1)}{2(2x-1)(2x+1)}$ = $\frac{2}{2x-1}$.

Thứ 4, ngày 5 tháng 8 năm 2026 - duchuy198661 - hoidap247.com