Question

company will enclose a rectangular area of 12 comma 600 ft squared12,600 ft2 in the rear of its plant. One side will be bounded by the building and the other three sides by​ fencing, as shown to the right. If 320 ft320 ft of fencing will be​ used, what will be the dimensions of the rectangular​ area?

Answer 1

2 x + y = 320

x y = 12,600 so y = 12,600/x

2 x + 12,600/x = 320

x^2 + 6,300 = 160 x

x^2 - 160 x + 6,300 = 0

x = [160+/-sqrt(25600-25200)]/2

x = [ 160 +/- 20] /2

x = 90 or 70
try 90
then y = 140
2x + y = 320 Yes, that works
try 70
y = 180
2x+ y = 140 + 180 = 320, Yes that works