Arectangular swimming pool that is 10 ft wide by 16 ft long is surrounded by a cement sidewalk of uniform width. if the area of the sidewalk is 155 ft2, what is its width? a = lw

Let 's x the width of the sidewalk.

Area of the swimming pool= 10*16=160 (ft²)
Area of the sideway+the swimming pool= (16+2x)*(10+2x) =160+155

==>160+20x+32x+4x²=160+155
==>4x²+52x-155=0
Δ=52²+4*4*155=5184=72²
==>x=(-52+72)/2=5/2 or x=a negative to exclude.

Width of the sideway=5/2 ft
so tell me if i helped