SOLUTION: This is a simple algebra question: "Find the dimensions of a rectangle whose perimeter is 42 m and whose area is 104 m (squared)."

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Question 250839: This is a simple algebra question: "Find the dimensions of a rectangle whose perimeter is 42 m and whose area is 104 m (squared)."
Answer by drk(1908) About Me  (Show Source):
You can put this solution on YOUR website!
we need two formulas:
P+=+2L+%2B+2W
A+=+LW.
From our given information we have
(i) 42+=+2L+%2B+2W
(ii) 104+=+LW
Solve equation (ii) for L.
(iii) L+=+104%2FW
Substitute (iii) information into (i) to get
(iv) 42+=+208%2FW+%2B+2W
or
(v) 21+=+104%2FW+%2B+W
Now multiply both sides by W to get
21W+=+104+%2B+W%5E2
set this equal to 0 and factor.
w%5E2+-+21W+%2B+104
%28W-13%29%28W-8%29+=+0
W = 13, W = 8.
If W = 13m, then L = 8m.
If W = 8m, then L = 13m.