9(x)的平方+12x+4=(x-1)的平方
(3x+2)²=(x-1)²
(3x+2)²-(x-1)²=0
(3x+2+x-1)(3x+2-x+1)=0
(4x+1)(2x+3)=0
x1=-1/4 x2=-3/2