Answers

2016-07-31T20:06:25+08:00
LW = 84
L + W = 38
L = 38 - W

Substitution:
(38 - W)W = 84
38W - W^2 = 84
[-W^2 + 38W - 84 = 0] -1 
W^2 - 38W + 84 = 0
This is not factorable
Using quadratic formula:
-b ± √(b^2 - 4ac) all over 2a
You'll get:
W = 19 ± √277 
W = 35.64; W = 2.36 (approximately)
L = 38 - W (according to our previous equations)
L = 38 - 35.64 =2.36; L = 38 - 2.36 = 35.64

The answer could actually be
W=35.64 L=2.36
or W=2.36 L=35.64
But since it is usual that the width is shorter than the length, you might wanna consider the former
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