Question

You would like to construct a 400-square-foot rectangular garden along your driveway. The fencing on the driveway side costs $15 per linear foot, while the fencing for the other three sides costs $8 per linear foot. Write an expression for the cost of the enclosed rectangular garden as a function of the length L of the garden.

Answer 1

x+3y=400
15x+8*3y=L

15(400-3y)+8*3y+L

Answer 2

Not quite...

The cost C is

C = 8(2W+L)+15L
since LW=400,
= 8(2(400/L)+L) + 15L
= 8(800/L + L) + 15L
= 6400/L + 23L

Answer 3

Thank you Steve :)