Question 1099105
<pre>
The first equation has two equal signs, which is not allowed.
So we can't solve it for you.

x=2y+z=9
x-y+3z=13
    2z=10

Solve 2z=10 to find z, which is pretty easy.
Substitute what you get for z in the first two equations.
Solve one of them for x or y and substitute in the other one.
That's the best we can do.

Edwin</pre>