(x^3+3x+2)(4x^2+8x+3)+90
问题描述：
(x^3+3x+2)(4x^2+8x+3)+90
错了,纠正一下(x^2+3x+2)(4x^2+8x+3)+90 ,用换元法因式分解,急,
答
原式=（x+1)(x+2)(2x+1)(2x+3)+90
=(x+1)(x+1+1)(2(x+1)-1)(2(x+1)+1)+90
令x+1=y
则原式=y*(y+1)(2y-1)(2y+1)+90