When solving problems, which of these is performed before the others? a. multiplication b. addition c. exponents d. subtraction

From that list, the exponents should be handled first.

Here's the memory device for the order of operations
that I often see here on .  I didn't learn it this way,
but this is a good and handy thing to remember:
 
               P  E  M  D  A  S

It stands for the order in which operations should be performed
if you're working to simplify an expression that has several different
operations in it.

Parentheses
Exponents
Multiplication
Division
Addition
Subtraction