Combining like terms simplify each expression 12r + 5 + 3r - 5

Like terms are terms that have the same variable(s) (or lack thereof) and are to the same power.

In the expression above, 12r and 3r are like terms because they both have the variable r and are to the same power.

Likewise with 5 and -5. They both have no variables and are to the same power.

Combine.

12r + 5 + 3r - 5 = 15r + 0 or just 15r

So, 15r is the answer.