Question

设f(x)=ax²-bx+2，且f(-5)=17，则f(5)=?

详细过程
参考答案写的是：-13

Answer 1

f(x)=ax²-bx+2，且f(-5)=17
f(-5)=A(-5)^2-B(-5)+2=17 ==>A(5)^2+B(5)=15
又F(5)=A(5)^2-5B+2=25A-5B+2=17-10B

题目似乎有问题,条件不够!!!

Answer 2

f(-5)=25a^2+5b+2=17
f(5)=25a^2-5b+2=(25a^2+5b+2)-10b=17-10b