Question 311588
(x+7)^2=225
x^2+14x+49=226
x^2+14x+49-225=0
x^2+14x-176=0
(x-8)(x+22)=0
x-8=0
x=8 ans. for the length of the original side of the square.
Proof:
(8+7)^2=225
15^2=225
225=225