x^2+x-12=(x+4)(x-3)=0x=3,x=-4x^2+4x+8=2x+11 x^2+2x-3=(x+3)(x-1)=0x=1,x=-3x(x-4)=2-8xx^2+4x-2=0x=2+根号6,x=2-根号6x^2+2x=0x(x+2)=0 x=0,x=-2