分解得x^2-4x+4=4x^2+12x+93x^2+16x+5=0(x+5)(3x+1)=o得x1=-5,x2=-1/3
(x-2)^2-(2x+3)^2=0(x-2+2x+3)(x-2-2x-3)=0X1=1/3 X2=-5