Question 515173
width =x
length =2x

side walk = 3 ft

width including sidewalk = x+6
length including sidewalk = 2x+6

Area = L*W
Area = (x+6)(2x+6)
A(x) = 2x^2+18x+36 
----
2x^2+18x+36 =99

2x^2+18x+36-99=0

2x^2+18x-63=0

Find the roots of the equation by quadratic formula						
						
a=	2	,b=	18	,c=	-63	
						
b^2-4ac=	324	+	504			
b^2-4ac=	828					
{{{x=(-b+-sqrt(b^2-4ac))/(2a)}}}						
{{{x1=(-b+sqrt(b^2-4ac))/(2a)}}}						
{{{x1=(-12+21)/(4)}}}						
x1=(	-18	+	28.77	)/	4	
x1=	2.69					
x2=(	-18	-28.77	) /	4		
x2= 	-11.69					
Ignore negative value

Dimensions of pool						

width = 2.69 ft
length = 5.38 ft

m.ananth@hotmail.ca