Bài 2:
a,
$49:x=(-5)+12$
$\to 49:x=7$
$\to x=49:7$
$\to x=7$
b,
$56-4|x|=32$
$\to 4|x|=24$
$\to |x|=6$
$\to x=±6$
c,
$|x-3|-2^2·3=(-8)$
$\to |x-3|-4·3=-8$
$\to |x-3|-12=-8$
$\to |x-3|=4$
$\to \left[\begin{array}{l}x-3=4\\x-3=-4\end{array}\right.$
$\to \left[\begin{array}{l}x=7\\x=-1\end{array}\right.$