Answer: x = 15
Explanation:
The perimeter is the sum of the 2 lengths and 2 widths.
Step 1: 2 times the length is 4x + 10
Step 2: 2 times the width is 2x - 20
Step 3: Add the both results together.
6x - 10
Step 4: Create an algebraic equation.
6x - 10 = 80
Step 5: Solve for x.
6x = 90
6x/6 = 90/6
x = 15