Question 71023
garden=30*40=1200 ft^2
garden+walkway=1800 ft^2
let walkway width be x ft. then
(30+2x)*(40+2x)=1800
1200+80x+60x+4x^2=1800
4x^2+140x+1200-1800=0
4x^2+140x-600=0
using the quadratic equation we get
x=(-b+-sqrt[b^2-4ac])/2a
x=(-140+-sqrt[140^2-4*4*-600])/2*4
x=(-140+-sqrt[19600+9600)/8
x=(-140+-sqrt29200])/8
x=(-140+-170.88)/8
x=(-140+170.88)/8
x=30.88/8
x=3.86 feet for the walkway