x-x(3x+2)=15-3x(x+2)
x-3x2-2x=15-3x2-6x
x-3x2-2x+3x2+6x=15
5x=15
x=15/5
x=3
(x-2)2-16=0
(x-2-4)(x-2+4)=0
(x-6)(x+2)=0
x-6=0 hoặc x+2=0
x=6 hoặc x=-2
(x+5)2-(2x-1)2=0
(x+5-2x+1)(x+5+2x-1)=0
(6-x)(5+3x)=0
6-x=0hoặc 5x+3=0
x=6 hoặc x=\(\frac{-3}{5}\)