Question

5x + 2y + z = –2
3x + 4y + 3z = 2
–4x – 3y – 3z = 1

Answer 1

can you use matrices on a TI-83 or in excel?

Answer 2

If not, here it is by hand:
combine two eq's that most easily eliminate a variable, in this case Eq's 2 and 3:
3x + 4y + 3z = 2
–4x – 3y – 3z = 1
Add (vertically) the corresponding terms:
-x +y +0 = 3

Then combine one of these with Eq #1 to also eliminate z:
multiply all the terms in Eq #1 by 3:
3(5x + 2y + z = –2) --> 15x + 6y +3z = -6
and combine with Eq 3 to eliminate z

Answer 3

I prefer Excel because there are fewer opportunities for errors