ax的平方+2x(b-2x)+b+2=0ax²+2bx-4x²+b+2=0ax²-4x²+2bx+b+2=0(a-4)x²+2bx+b+2=0△=4b²-4(a-4)(b+2)=4b²-4(ab-4b+2a-8)=4(b²-ab+4b-2a+8)x=[-b±√(b²-ab+4b-2a+8)]/(a...