Answer:
9b + 99
Step-by-step explanation:
You have already seen what the example had done.
First multiply (factorize) 9 to both variables inside the parentheses.
9 · b = 9b
9 · 4 = 36
Now remember to not change the sign in the parentheses
9b + 36 + 63
You can now add 63 and 36 together.
63 + 36 = 99
So,
9b + 99
It is still "plus" sign because the number 99 is a positive.
