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March 29, 2015

March 29, 2015

Posted by **Katie Lee** on Thursday, September 15, 2011 at 11:42pm.

Sol'n:

5x+3y = -11 ---(1)x 2, 10x + 6y = -22 ----(1')

7x-2y = 19 ---(2)x 3, 21x - 6y = 57 ----(2')

add 1' and 2'

31x = 55, divide by 31 on both side to obtain the value of x,

x = 35/31

then find y: from (2)

7(35/31) - 19 = 2y

2y = -344/31, then divide by 2 on both side to obtain the value of y.

y = -172/31

thus

x = 35/31 and y = -172/31 <----- answer

How do you get -344/31 in this problem?

- Math -
**Reiny**, Thursday, September 15, 2011 at 11:49pmthe steps are correct.

from

7x-2y=19

7x - 19 = 2y

7(35/31) - 19 = 2u

245/31 - 589/31 = 2y

-344/31 = 2y

-172/31 = y

- Math -
**Katie Lee**, Thursday, September 15, 2011 at 11:54pmhow did you get -589?

- Math -
**Reiny**, Friday, September 16, 2011 at 12:00am19/1 = ?/31

- Math -
**Katie Lee**, Friday, September 16, 2011 at 12:05amThank you so much I have been working on this problem 308 times and can not figure this out

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