x⁴-2x²y-3y²+8y-4

问题描述:

x⁴-2x²y-3y²+8y-4

原式=x⁴-2x²y+y²-4y²+8y-4
=(x²-y)²-(2y-2)²
=(x²-y-2y+2)(x²-y+2y-2)
=(x²-y+2)(x²+y-2)