(x的平方-1)(x+3)(x+5)+15
问题描述：
(x的平方-1)(x+3)(x+5)+15
因式分解
答
=(x-1)(x+1)(x+3)(x+5)+15=(x-1)(x+5)(x+1)(x+3)+15=(x²+4x-5)(x²+4x+3)+15=(x²+4x)²-2(x²+4x)-15+15=(x²+4x)²-2(x²+4x)=(x²+4x)(x²+4x-2)