Question 171266
 Need help here, please with systems of linear equations in 3 variables!
I don't understand it at all. It's very confusing to me. 
3x^2+4y+z=7
2y+z=3
-5x+3y+8z=-31 
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You say linear, but the 1st eqn is 2nd order.  Is that a typo?

PS I thought I just posted this.