Answer:
Step-by-step explanation:
l^2=A
also l^2=x^2
x²=4x+12
x²-4x-12=0
x²-6x+2x-12=0
x(x-6)+2(x-6)=0
(x-6)(x+2)=0
x=6
x=-2 (rejected)
side length=6 inches