SOLUTION: Please help me solve this problem. The length of a rectangle is three times its width. If its length is increased by 2m and its width is decreased by 1m, the area of the new recta

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Question 886204: Please help me solve this problem.
The length of a rectangle is three times its width. If its length is increased by 2m and its width is decreased by 1m, the area of the new rectangle is 68m^2. Find the dimensions of the original rectangle.

Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
let w be width, then length = 3w
Area of rectangle(A) = length times width
68 = (3w+2) * (w-1)
68 = 3w^2 -w -2
subtract 68 from both sides of =
3w^2 -w -70 = 0
(3w+14) * (w-5) = 0
w = -14/3 or 5
we want the positive value for w
therefore the length = 15 and width = 5
check answer
68 = (15+2) * (5-1) = 17 * 4 = 68
our answer checks