Răspuns:
a)4(2-x)=x-2
8x-4x=x-2
4x=x-2
4x-x=-2
3x=-2
x=-2/3
b2[21-3(5-2x)]=0
2(21-15+6x)=0
2(6+6x)=0
12+12x=0
12x=-12
x=-12/12=-1
