Expression for perimeter is 2(14-x + x) = 28
Step-by-step explanation:
Step 1:
Given expression for area of the rectangle = a(x) = x(14-x) where x is the width. Then length = 14-x since area = length × width
Step 2:
Find expression for perimeter of the rectangle.
Perimeter of the rectangle = 2(length + width) = 2(14 - x + x) = 2 × 14 = 28