Giải thích các bước giải:
a.$2(x-4)-3(x-5)=4(3-x)-18$
$\to 2x-8-3x+15=12-4x-18$
$\to (2x-3x+4x)=12-18+8-15$
$\to 3x=-13$
$\to x=\dfrac{-13}3$
b.Để $-2x-11\quad\vdots \quad 3x+2$
$\to 2x+11\quad\vdots \quad 3x+2$
$\to 3(2x+11)\quad\vdots \quad 3x+2$
$\to 6x+33\quad\vdots \quad 3x+2$
$\to (6x+4)+29\quad\vdots \quad 3x+2$
$\to 2(3x+2)+29\quad\vdots \quad 3x+2$
$\to 29\quad\vdots \quad 3x+2$
$\to 3x+2\in \{1,-1,29,-29\}$
$\to x\in\{-1, 9\},x,\in Z$
