Question 119652
(30+2X)(40+2X)=1440 X BEING THE WIDTH OF THE WALKWAY.
1200+80X+60X+4X^2=1440
4X^2+140X+1200-1440=0
4X^2+140X-240=0
4(X^2+35X-60)=0
USING THE QUADRATIC EQUATION WE GET:{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 
X=(-35+-SQRT[35^2-4*1*-60])/2*1
X=(-35+-SQRT[1225+240])/2
X=(-35+-SQRT1465])/2
X=(-35+-38.28)/2
X=(-35+38.28)/2
X=3.28/2
X=1.64 ANSWER.
X=(-35-38.28)/2
X=-73.28/2
X=-36.64 ANSWER.