need help with question

Question

Justine wants to put a deck in the corner of her backyard in the shape of a right triangle. The length of one side of the deck is 7 feet more than the other side. The hypotenuse is 13. Find the length of two sides of the deck.

Answer 1

x^2+(x+7)^2=13^2

x^2+x^2+14x+49=169

2x^2+14x-120=0

x^2+7x-60=0

factor

(x-5)(x+12)=0

x-5=0

x=5 feet

x+7=12 feet