Question

The dimensions of a square are altered so that one dimension is increased by 5 feet, while the other is decreased by 3 feet. The area of the resulting rectangle is 84 ft2. What was the perimeter of the original square?

PLEASE HELP

Answer 1

36

Explanation:

square with 4 sides all equal call it a

so (a+5) * (a-3) =84

a²+2a-15=84

solve: a²+2a-99=0

Use the quadratic formula

a = 9 or -11

so a = 9

perimeter of the original square = 4*9 =36