Answer:
Width = 86 feet
Step-by-step explanation:
Create two equations with the info:
L = 27 + W
where L represents the length and W the width of the backyard.
The other one is about the area of the rectangular backyard:
Area = L x W
where you replace the area with 9718 and the length (L) with (27 + W):
[tex]Area= L\,*\,W\\9718=(W+27)\,W\\9718=W^2+27\,W\\W^2+27\,W-9718=0[/tex]
and solve for W using the quadratic equation:
[tex]W=\frac{-27+/-\sqrt{27^2-4(1)(-9718)} }{2\,(1)} \\W=\frac{-27+/-\sqrt{39601}}{2} \\W=\frac{-27+/- 199}{2}[/tex]
This gives us two solutions:
W = - 113
and W = 86
We use the positive solution since this is a distance.
Therefore the width is: 86 feet