Answer:
16xy + 4x + 3y + 8
Step-by-step explanation:
15xy - 13 + 4x + 3y + xy + 21
In order to simplify this expression we have to combine like terms
15xy + xy = 16xy
-13 + 21 = 8
Now we can rewrite the expression using the simplified terms
16xy + 4x + 3y + 8
