SOLUTION: Here is the question: If the length of a rectangular field is 8 feet more than double its width. Find the dimensions of the filed if its area is 540 square feet? I know y

Question 10210: Here is the question:

If the length of a rectangular field is 8 feet more than double its width. Find the dimensions of the filed if its area is 540 square feet?

I know you have to use A = l * w, but how do you start. I started like this:
540 = (8 + x) ( x^2)
would it then be : 540 = 8x + x^2?
Then do you have to subtract 540 from the left side to bring it to the right?

8x + x^2 - 540 = 0

I'm lost. Please help. I appreciate all your help. Thank you.
Answer by Earlsdon(6294) (Show Source): You can put this solution on YOUR website!
Well, you've got the right idea!
A = L*W but L = 2W+8 Because the length (L) is 8 ft more (+8) than twice the width (2W).

Subtract 540 from both sides.
Solve this quadratic for W. Factor a 2 to simplify it a bit.
Since this doesn't factor you can solve it by using the quadratic formula:
Here, a = 1, b = 4, and c = -270.

or
or
or Discard the 2nd solution as width can only be positive. Note: approx, so I rounded it to 33.106 Finally:
The length = 2W+8 = 2(14.55)+8 = 29.1+8 = 37.1 ft.
The width = 14.55 ft.
Check:
A = L*W = (37.1)(14.55) = 539.805 sq.ft. which is pretty darn close to 540 sq.ft.

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