The problem is:
2x + 5y + 4z = 21
4x - 5y +z = 38
6x - z = 17
step by step please.
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.