Question

Solve the following system of equations.

x + 3y - z = 2
x - 2y + 3z = 7
x + 2y - 5z = -21

Can anyone explain how to do this to me, please?

Answer 1

You can do this with a graphing calculator ( cheat)
or
you can do it on paper.

Answer 2

How do you do it on paper, like, work it out?

Answer 3

x-2y+3z=7 (second problem)
x+2y-5z=-21(third problem)
Combine
x-2z=-14

Answer 4

x+3y-z=2
x-2y+3z=7
you want one of the variables to cancel each other out.
2x+6y-2z=4 (multiply by 2)
3x-6y+9z=21 (multiply by 3)
combine
5x+7z=25