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July 29th, 2015, 11:12 AM  #1 
Newbie Joined: Jul 2015 From: Texas Posts: 2 Thanks: 0  Linear Equations 4 Variables
I usually don't have problems solving these, but this one is really quite annoying for some reason. y+z+w=6 z+2w+x=8 3w+x+y=10 x+y+z=9 From there, I got here wx+y=2 2wy=1 wx=3 And then was stuck. Help? 
July 29th, 2015, 11:19 AM  #2 
Senior Member Joined: Jun 2015 From: England Posts: 905 Thanks: 271 
number the equations 1, 2, 3 and 4 From equation 1) y+z = 6w equation 5 add equations 2 and 3 to form equation 6 Substitute for y+z in equation 6 and in equation 4 You now have two equations in two unknowns x and w you should be able to solve it all from there. 
July 29th, 2015, 11:38 AM  #3 
Global Moderator Joined: Oct 2008 From: London, Ontario, Canada  The Forest City Posts: 7,929 Thanks: 1124 Math Focus: Elementary mathematics and beyond 
x  w = 3 3w + z = 5 x + y  z = 5 $\displaystyle \implies$ z = 2. It's easy to finish from there. 

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