Answer:
x = 60 ft
Step-by-step explanation:
The area of the old parking lot is ...
Old Lot Area = Overall Area - School Area
= (165+75)(300+75) -(165)(300) = 40500 . . . ft^2
The area of the expanded parking lot is ...
(165 +75 +x)(300 +75 +x) -(165)(300) = x^2 +615x +40500
We want this to be twice the area of the Old Lot, so we want ...
2·40500 = x^2 +615x +40500
x^2 +615x -40500 = 0 . . . . put into standard form
(x +675)(x -60) = 0 . . . . . . . factor
x = 60 . . . . . . the positive solution
The old parking lot was expanded by 60 feet to make the expanded lot.
