x³-5x²+8x-4=x³-x²-4x²+4x+4x-4=x²(x-1)-4x(x-1)+4(x-1)=(x-1)(x²-4x+4)=(x-1)(x-2)²请借鉴上题,看x³-5x²+8x+4能否进行因式分解