Answer:

Explanation:

To combine like terms we need to remove the parenthesis
Multiply negative inside the second parenthesis

Now combine like terms
The terms that has same variable are like terms
-3y^2 and -4y^2 are like terms so its -7y^2
-7y and -6y are like terms so it becomes -13y
-9 and -9 are like terms so it becomes -18
Answer is
