Answers

2014-07-02T20:48:30+08:00
Let l be the original length
   w be the original width

l = 2w

Area of a rectangle = lw
A = (l - 3)(w +2)

But, l = 2w

A = (2w - 3)(w + 2) Applying the FOIL (First, Outer, Inner, Last) Method:
A = 2w^2 + 4w - 3w - 6 But, A = 30

2w^2 + w - 6 = 30
2w^2 + w - 36 = 0
(2w + 9)(w - 4) = 0
2w + 9 = 0
w = -9/2 But, the dimensions of a polygon can't be negatiive!!

w - 4 = 0
w = 4

l = 2w
l = 2*4 = 8

Width = 4cm
Length = 8 cm
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