SOLUTION: The length of a rectangle measures 4 cm less than 4 times the width. If the area is 31.0 cm^2, find the dimensions.

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Question 122434: The length of a rectangle measures 4 cm less than 4 times the width. If the area is 31.0 cm^2, find the dimensions.
Answer by ddreamfox(6) About Me  (Show Source):
You can put this solution on YOUR website!
Let x = width
4x-4 = length (4 cm less than 4 times the width)
since Area = length X width
Substitute values... to eqtn of Area
31 = x(4x-4)
31 = 4x2 - 4x
0 = 4x2 - 4x - 31
Using quadratic formula,x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
You'll get 2 values 1 positive and 1 negative...
The correct answer is the positive answer which is 3.328cm (rounded off)