Let f(x) = 1/(x+7)+15/(x-8). Find all a for which f(a)=f(a+15).

How do I solve this problem?

I understand this so far
f(a)=f(a+15)
1/(7+a) + 15/(a-8) = 1/(a+22) + 15/(a+7)

I am lost after that

This is a multiple choice question and I am not getting any of the choices

a.) -161/8
b.) 120/7
c.) 161/7
d.) -17

1 answer

I did it in my head and I didn't get any of the answers either. I recommend you do as I told, recheck once more.