Bạn tham khảo:
$-5 - 4( x + 1 ) = 15 - 6x$
$⇔ -5 - 4x - 4 = 15 - 6x$
$⇔ -4x + 6x = 15 + 5 + 4$
$⇔ 2x = 24$
$⇔ x = 24 ÷ 2$
$⇔ x = 12$
$-7( 2 - x ) - 3( x + 1 ) = 2x - 3$
$⇔ -14 + 7x - 3x - 3 -2x = -3$
$⇔ -x = -3 + 3 + 14$
$⇔ 2x = 14$
$⇔ x = 7$
$x^{2} - 2x = 0$
$⇔ x( x - 2 ) = 0$
$⇔$ \(\left[ \begin{array}{l}x=0\\x=2\end{array} \right.\)