x=-1,2使原式为0,所以(x+1),(x-2)是原式的因式原式=(4x^4-8x^3)-(8x^3-16x^2)-(7x^2-14x)+(5x-10)=(x-2)(4x^3-8x^2-7x+5)4x^3-8x^2-7x+5=(4x^3+4x^2)-(12x^2...第二步的(x-2)是怎么提出来的?(4x^4-8x^3)-(8x^3-16x^2)-(7x^2-14x)
+(5x-10)=4x^3(x-2)-8(x^2)(x-2)-7x(x-2)+5(x-2)
=(x-2)(4x^3-8x^2-7x+5)