Answer:
5x - 5
Step-by-step explanation:
To find the missing side, add the two sides together and subtract them from the perimeter.
side 1 + side 2
3x + 2 + 8x + 7
combine like terms
11x + 9
Subtract from the perimeter
16x + 4 - (11x + 9)
rewrite as an addition problem, so you need to change the signs inside the parentheses.
16x + 4 + (-11x -9)
Now combine like terms
5x - 5
