已知x的平方-8x-3=0,求(x-i)(x-3)(x-5)(x-7)的值
问题描述:
已知x的平方-8x-3=0,求(x-i)(x-3)(x-5)(x-7)的值
答
x²-8x-3=0
x²-8x=3
(x-1)(x-3)(x-5)(x-7)
=(x-1)(x-7)(x-3)(x-5)
=(x²-8x+7)(x²-8x+15)
=(3+7)(3+15)
=10*18
=180