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January 30, 2015

January 30, 2015

Posted by **susie** on Monday, April 4, 2011 at 7:14pm.

- area, perimeter -
**Damon**, Monday, April 4, 2011 at 7:38pmperimeter = 2*5+2*3 = 16

2L + 2 W = 16 so L+W=8

WL = 16 so W = 16/L

L + 16/L = 8

L^2 + 16 = 8L

L^2 -8L + 16 = 0

(L-4)(L-4) = 0

L = 4

B = 16/L = 4

- area, perimeter -
**Reiny**, Monday, April 4, 2011 at 7:46pmfrom the first description

length ---- x

width ---- y

xy = 2x + 2y

xy - 2y = 2x

y(x-2) = 2x

y = 2x/(x-2)

2nd rectangle is 5 by 3, so its perimeter is 30

so now we know 2x+2y = 30

or x+y = 15

y = 15-x

sub that into the other equation, so

2x/(x-2) = 15-x

2x = 15x - x^2 - 30 + 2x

x^2 -15x + 30 = 0

by the formula

x = 12.623, and subbing back: y = 2.376

or x = 2.376 and subbing back x = 12.623

(notice 2.376 x 12.623 = 29.992 or 30 as expected

- Scrap my answer, go with Damonseter -
**Reiny**, Monday, April 4, 2011 at 7:49pmI must have have a had a brain-twitch

A 3 by 5 rectangle has a perimeter of 30 ????

Come on Reiny !!!!

- area, perimeter -
**private name**, Wednesday, April 20, 2011 at 8:56pmi dont get that helppp

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