A22-ft by 28-ft rectangular swimming pool is surrounded by a walkway of uniform width. if the total area of the walkway is 336 ft2, how wide is the walkway?

1) we calculate the area of  the swimmning pool
area of this swimming pool=(22ft)(28 ftt)=616 ft².

2) we calculte the total area of the swimming pool + area of the walkway
Total area=area of the swimming pool + area of the wakway
Total area=616 ft²+336 ft²=952 ft².

3) we can suggest this equation :
x=width
(22+2x)(28+2x)=952
616+44x+56x+4x²=952
4x²+100x-336=0
x²+25x-84=0

x=[-25⁺₋√(625+366)]/2=(-25⁺₋31)/2
we have two solutions:
x₁=(-25-31)/2=-28 this solution is not valid.
x₂=(-25+31)/2=3

the width of the walkway is 3 ft. 

(6,0) i hope it makes enough sense