[jananewbould]

So I have this problem:

x + 2y + z = 0
-3x + 3y + 2z= -7
4x - 2y - 3z= 2

Does anyone know the steps I should use to solve this using substitution?
HELP!

Thanks
Jana

[ebaines]

Usually the best place to start is to look at the equations and decide which would be easiest to rearrange to get either the x, y, or z by itself on one side. In this case the first equation looks simplest, since neither the x nor z term have coefficient and the right hand side is zero. So pick either the x or z and get it all alone on one side of the equation. For example, you can rearrange it to get:
x = 0-2y-z = -2y +z.
Now sub for that in the other two equations:

-3(-2y-z) + 3y +2z = -7
4(-2y-z) -2y - 3z = 2

You now have 2 equations in 2 unknowns. Can you take it from here?

[nuclear_sugar]

I remember when I learned it... but I can't remember much about the solution, except that you have to "add the equations" together, like putting them as you had written them above, then adding each variable together... but I think you somehow have to do it as many times as you have variables, and for that, I CANNOT remember how! I even made straight A's in it, but it's been a decade since I've used it. Sorry! Good luck!

[Unknown008]

That method I think is called elimination method, whereby you get rid of some variables, leaving those you can deal with more easily

[Mckenzie1046]

The question was concerning how to use elimination in solving the equation. The answer given was how to solve the equation by substitution and therefore not helpful.