x的4次方减2x的2次方加5x减4因式分解
问题描述：
x的4次方减2x的2次方加5x减4因式分解
答
x^4-2x^2+5x-4
=(x^4-2x^2+1)+5x-5
=(x²-1)²+5(x-1)
=(x+1)²(x-1)²+5(x-1)
=(x-1)[(x+1)²(x-1)+5]
=(x-1)(x³+x²-x+4)