整式的加减 (15 17:26:8)
问题描述：
整式的加减 (15 17:26:8)
已知Y=a*x^5+b*x^3+c*x-5,当X=-3时,Y=7,那么X=3时,求Y的值
答
X=-3时
y=a*(-3)^5+b*(-3)^3-3c-5
=-(a*3^5+b*3^3+3c)-5
=7
a*3^5+b*3^3+3c=-12
x=3时
y=a*3^5+b*3^3+3c-5=-12-5=-17