SOLUTION: The length of a rectangle is 4 feet longer than its width, and its area is 10 sq. feet. Find the length and the width.

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Question 210959: The length of a rectangle is 4 feet longer than its width, and its area is 10 sq. feet. Find the length and the width.

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Start with:
A+=+L%2AW Substitute A = 10 and L = W+4.
10+=+%28W%2B4%29%2AW Simplify.
10+=+W%5E2%2B4W Subtract 10 from both sides.
W%5E2%2B4W-10+=+0 Use the quadratic formula to solve:W+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a and a = 1, b= 4, and c = -10.
W+=+%28-4%2B-sqrt%284%5E2-4%281%29%28-10%29%29%29%2F2%281%29 Evaluate.
W+=+%28-4%2B-sqrt%2816-%28-40%29%29%29%2F2
W+=+%28-4%2B-sqrt%2856%29%29%2F2
W+=+%28-4%2B-sqrt%284%2A14%29%29%2F2
W+=+-2%2Bsqrt%2814%29 or W+=+-2-sqrt%2814%29
highlight_green%28W+=+1.74%29 or cross%28W+=+-5.74%29 Discard the negative solution.
The width is 1.74 feet and the length is 5.74 feet. (Approximately)