Answer:
Option C. 10.5(12 + x) square feet
Option E. (126 + 10.5x) square feet
Explanation:
step 1
Find the area of the original living room
we know that
The area of the original living room is equal to

we have

substitute

step 2
Find the new area of the living room
The length of the room is being expanded by x feet
so
we have

The new area is

The expanded form of the expression is
Apply distributive property
