How many pairs of positive integers (a,c) satisfy a^3+125=c^3?

A. 0
B. 1
C. 2
D. 3

How Do i figure this out?

1 answer

I can only see
(0,5) and (-5,0)

the right side has to be a perfect cube
so it could be 1,8,27,64,125, 216
which means that a^3 + 125 must be one of those numbers, and a^3 would be one of
those : 124, 117, 98, ...

does not look too promising other than the 2 I stated