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December 22, 2014

December 22, 2014

Posted by **Kevin** on Thursday, February 26, 2009 at 8:31am.

5x+2y+z=-25

5x-3y-z=-23

3x+y+2z=-9

- algebra -
**Reiny**, Thursday, February 26, 2009 at 8:41amI would use elimination and start with the z's

Add the first plus the second to get

10x - y = -48

Double the second and add it to the third to get 13x - 5y = -55

ahhh, changed my mind, let's now switch to substitution

from above 10x - y = -48 or

y = 10x + 48

sub that into

13x - 5y = -55

13x - 5(10x + 48) = -55

etc. (I got x=5)

I am sure you can finish it from here.

- algebra -
**Kevin**, Thursday, February 26, 2009 at 8:57amI am coming up with (-5,-2,4) for my answer and I see you x=5

- algebra -
**Reiny**, Thursday, February 26, 2009 at 10:20amgood job

You can tell your answers are correct by merely subbing them back into the 3 original equations, they work

TRUST YOURSELF

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