(x+3)^2-16(x+2)^2=0
(x+3)^2= 16(x+2)^2
x+3 =正负 4(x+2)
x+3 = 4x+8 时
3x = -5
x = -5/3
x+3 = -4x-8 时
5x = -11
x = -11/5