Math
posted by LP .
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.

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