Hello!
The answer is:

Why?
To find the resultant expression, we need to apply the distributive property.
It can be defined by the following way:

Also, we need to remember how to add like terms: The like terms are the terms that share the same variable and exponent, for example:

We were able to add only the two first terms since they were like terms (they share the same variable and the same exponent)
So , we are given the expression:

Then, applying the distributive property, we have:

Hence, the answer is:

Have a nice day!