解(1)（X-6)(X+2)=0 X=6或X=-2解(2)x²-4x+4-4-12=0(X-2)²-16=0(X-2)²=16X-2=±4X=2±4X=6或X=-2
解：x^2-4x-12=0(x-6)(x+2)=0x=6orx=-2两解
解：x²-4x-12=0(x-6)(x+2)=0x-6=0或x+2=0x=6或x=-2
