Answer:
7x+4
Step-by-step explanation:
We have a rectangle
The perimeter is 18x+4
We know the formula for perimeter is
P =2 (l+w)
We know the width is 2x-2
18x+4 = 2 (l+2x-2)
Divide each side by 2
(18x+4)/2 = 2 (l+2x-2)/2
9x+2 = (l+2x-2)
Subtraxt 2x from each side
9x-2x +2 = l +2x-2-2x
7x+2 = l-2
Add 2 to each side
7x+2+2 = l-2+2
7x+4 = l
The unknown side is
7x+4
