algebra

*edit* formatting got messed up (even though it looked fine in preview...)

Can't seem to insert a newline inside the <pre> </pre>  tags.

And now I can't even edit my first response.

Anyway, here's a screenshot of my answer taken from the preview:

Check

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Add 2^nd and 3rd

7x + 9z = 11

Multiply 1st by 2  and add to 2nd

10x +5z=0          mutiply red by -10/7 and add to green    

-10/7 (9z)+5z = -10/7 (11)    solve for z

z = 2

Plug z value into 2nd equation      and     3rd equation

2x - 2y = 4                                                 5x -2y = -11         add these two equations

7x = - 7    

x = - 1

Now sub in the values of z and x into any of the equations to compute z

2(- 1) + 2y +3(2) = 10

y = 3