A Quadratic Word Problem

The length of a rectangular garden is 4 yards more than the width. The area of the garden is 60 square yards. Find the dimensions of the garden.

1 answer

W = Garden width

H = Garden height

A = Garden area

L = W + 4

A = L * W

60 = ( W + 4 ) * W

60 = W ^ 2 + 4 W Add 4 to both sides

64 = W ^ 2 + 4 W + 4

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Remark :

W ^ 2 + 4 W + 4 = ( W + 2 ) ^ 2

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64 = ( W + 2 ) ^ 2

W + 2 = sqrt ( 64 )

W + 2 = + OR - 8 Subtract 2 to both sides

W + 2 - 2 = + OR - 8 - 2

W = + OR - 8 - 2

Solutions :

W = 8 - 2 = 6

and

W - 8 - 2 = - 10

Width can't be negative so :

W = 6 in

L = W + 4 = 6 + 4 = 10 in