The length of a rectangular park is 3 feet shorter than 2/3 times its width if the length is 123 feet the width of the park in feet?

The length of a rectangle is three feet shorter than twice its width. If the are of a rectangle is 170ft^2, what is the length of the rectangle? 
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let width be x feet
length = 2x-3
Area = 170 ft^2
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Area = L*W
x(2x-3)=170

2x^2-3x=170
2x^2-3x-170 =0
2x^2-20x+17x-170=0
2x(x-10)+17(x-10)=0
(x-10)(2x+17)=0
Take positive value x= 10 feetthe width
Length = 20-3 = 17 feet

Modify the values.