#### Answer

a) $log_{5}125=3$
b) $5^2=25$

#### Work Step by Step

The subscript, or number directly after $log$ is the base of the exponent. In both cases, it's five. The exponent in the first is 3, which will be on the other side of the equation. 125 will be after the base of 5.
Now in part B, the $log$ equation is the same as $5^2=25$. A base of five, an exponent of 2, and the answer of 25.
To put all of this simply, they are inverses of each other (with the way they were written).