Find the length of the rectangular plot

The width of a rectangular plot is 4 feet longer than two-fifths the length. If the perimeter of the plot is 36 feet, find the length. 

x = length
(2/5)x + 4 = width   {width is 4 longer than two-fifths the length} 

Perimeter of a rectangle is 2(width) + 2(length) 

2x + 2[(2/5)x + 4] = 36   {substituted into perimeter formula}
2x + (4/5)x + 8 = 36   {used distributive property}
(14/5)x + 8 = 36   {combined like terms}
(14/5)x = 28   {subtracted 8 from each side}
x = 10   {divided each side by 14/5, which is multiplying by reciprocal, 5/14} 

length is 10 feet

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