SOLUTION: I HAVE TO SOLVE FOR THREE VARIABLES IN THREE DIFFERENT SOLUTIONS. PLEASE HELP. 9x-y+z=-30 3x+2y-3z=-3 x-3y+2z=-12 i thought i knew how to figure it out but i have been at

Algebra ->  Equations -> SOLUTION: I HAVE TO SOLVE FOR THREE VARIABLES IN THREE DIFFERENT SOLUTIONS. PLEASE HELP. 9x-y+z=-30 3x+2y-3z=-3 x-3y+2z=-12 i thought i knew how to figure it out but i have been at      Log On


   

Question 166430: I HAVE TO SOLVE FOR THREE VARIABLES IN THREE DIFFERENT SOLUTIONS. PLEASE HELP.
9x-y+z=-30
3x+2y-3z=-3
x-3y+2z=-12
i thought i knew how to figure it out but i have been at this well over 20 minutes so any suggestions would be greatly appreciated.
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
eliminate the same variable from two different PAIRS of equations, leaving two new equations with two unknowns

multiply 2nd eqn by -3 and add to 1st eqn __ -7y+10z=-21

multiply 3rd eqn by -3 and add to 2nd eqn __ 11y-9z=33

multiplying 1st new eqn by 11 __ -77y+110z=-231

multiplying 2n new eqn by 7 __ 77y-63z=231

adding eqns __ 47z=0 __ z=0

substituting __ 11y-9(0)=33 __ y=3

substituting __ x-3(3)+2(0)=-12 __ x-9=-12 __ x=-3