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April 17, 2014

April 17, 2014

Posted by **alma20** on Friday, June 1, 2007 at 9:53am.

Use the echeclon method to solve the system of three equations in three unknowns

2x+4y+z = 22

4x - 4y -z = 2

4x +y =4z = 12

Matrix would be the prefered method, echelon is harder.

First, take eq1)

2x+4y+z = 22 add this to equation 2 to eliminate z

2x+4y+z = 22

4x - 4y -z = 2

6x=24 solve for x.

Now multipy equation 2) by 4

16x-16y-4z=8

add to equation three

4x +y +4z = 12 or

20x-15y=20 you know x, so solve for y.

Put x,y in any of the equations, solve for z.

This was NOT a good problem for echelon.

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