a)
$123-5.(x : 2+4)= 38$
$123-5($ $\frac{1}{2}$ $x+4$)$=38$
$123-$ $\frac{5}{2}$ $x-20=38$
$103-$ $\frac{5}{2}$ $x=38$
$206-5x=76$
$-5x=76-206$
$-5x = -130$
$x=26$
b)
(25-|x+1|)+12=5
25-|x+1|+12 = 5
37- |x+1|= 5
- |x+1|= 5 -37
- |x+1|= -32
|x+1|= 32
⇔ x+1 = 32 hoặc x+1 = -32
TH1 :
x+1 = 32
x = 32-1
x = 31
TH2 :
x+1 = -32
x = -32 -1
x = -33