Usually I would say to eliminate the x values first, but in this case it looks easier to eliminate the z's.

Do the following.

and

Now do

.

Now you can solve for x. .

Substitute this value into the other two equations to solve for y and z.

.

.

So your solution is [tex](x, y, z) = (4, -3, 7).

You could substitute these back into your original equation to check if you wish.