Question 360167
(20+2X)(28+2X)=1,100
560+56X+40X+4X^2=1,100
4X^2+96X+560-1,100=0
4X^2+96X-540=0
4(X^2+24X-135)=0
{{{X = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 
X=(-24+-SQRT[2462-4*1*-135])/2*1
X=(-24+-SQRT[576+540])/2
X=(-24+-SQRT1,116)/2
X=(-24+-33.4)/2
X=(-24+33.4)/2
X=9.4/2
X=4.7 FT. IS THE WIDTH OF THE WALKWAY.