Math Help - quadratic equation help

Hi, I have a problem but I can't figure out what the equation should be, (like what numbers I should be using)

A square exercise pen measuring 6 feet on each side needs to be expanded as the golden retriever pups grow bigger. By how much must each side be lengthened to increase the area to more than double the original area? The shape must be kept a square.

I've tried A= x^2 and x=6+y but that doesn't work :/

thanks!

Originally Posted by gigixx

A square exercise pen measuring 6 feet on each side needs to be expanded as the golden retriever pups grow bigger. By how much must each side be lengthened to increase the area to more than double the original area? The shape must be kept a square.

The original pen has an area of 36 square feet. Double the area would be 72 square feet. If you have a square enclosing an area of 72 feet, then what must the length of each side be?

If answer is an integer: 36 * 2 = 72 (must be exceeded); 9*9 = 81