Đáp án+giải thích các bước giải:
$\dfrac{x^2-x-6}{x-1}:\dfrac{x-3}{2x-2}$
$=\dfrac{x^2-x-6}{x-1}:\dfrac{x-3}{2(x-1)}$
$=\dfrac{(x^2-x-6)}{x-1}.\dfrac{2(x-1)}{x-3}$
$=\dfrac{(x^2-x-6).2(x-1)}{(x-1)(x-3)}$
$=\dfrac{2x^2-2x-12}{x-3}$
$=\dfrac{(2x^2-6x)+(4x-12)}{x-3}$
$=\dfrac{2x(x-3)+4(x-3)}{x-3}$
$=\dfrac{(x-3)(2x+4)}{x-3}$
$=2x+4$