Question 1066947
side is x
x^2 is area
make side x+3
area is (x+3^2)=x^2+6x+9=81
x^2+6x-72=0
(x+12)(x-6)=0
only positive root is x=6 inches, 
sides of original were 6 x 6 inches
when they become 9 x 9, the area is 81 sq inches.