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A rectangle has a length of 27 inches less than 4 times it’s width. If the area of the rectangle is 2790 square inches, find the length of the rectangle

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musiclover10045

Let the width = x

The length would be 4x-27

Area = length x width

2790 = (4x-27) * x

Expand:

2790 = 4x^2 - 27x

Subtract 2790 from both sides:

4x^2 - 27x - 2790 = 0

Use the quadratic formula to solve for the positive value of x:

X = -(-27) + sqrt(-27^2 -4*4(-2790)) /(2*4)

X = 30

Now replace x with 30 in the lengths:

Width = x = 30 inches

Length = 4x -27 = 4(30) -27 = 120-27 = 93 inches