Evaluate the expression.
This is NOT the answer but it SHOULD help you to UNDERSTAND how to evaluate an expression!
"To evaluate an algebraic expression, you have to substitute a number for each variable and perform the arithmetic operations. In the example above, the variable x is equal to 6 since 6 + 6 = 12. If we know the value of our variables, we can replace the variables with their values and then evaluate the expression."
Cited from www.mathplanet.com
Hope it helped you to understand how to do this!