SOLUTION: i am working on solving problems wit h3 variables. it has been over an hour and can't get a correct answer. it seems easy, but i am having no luck. if I could see the work to arri

Question 234909: i am working on solving problems wit h3 variables. it has been over an hour and can't get a correct answer. it seems easy, but i am having no luck.
if I could see the work to arrive the right answers that would be great. i have the answers in the back of my book.
2x-3y+z=5
x+3y+8z=22
3x-y+2z=12
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
2x-3y+z=5
x+3y+8z=22
3x-y+2z=12
-----------------------
Let the 2nd equation become the 1st:
x+3y+8z=22
2x-3y+z=5
3x-y+2z=12
-----------------
Subtract 2 times the 1st from the 2nd;
Subtract 3 times the 1st from the 3rd.
x+3y+8z=22
0-9y-15z=-39
0-10y-22z=-54
--------------------
Subtract 3rd from 2nd to get:
x+3y+8z=22
0+y+7z=15
0-10y-22z=-54
-------------------
Add 10 times 2nd to 3rd to get:
x+3y+8z=22
0+y+7z=15
0+0+48z=96
-------------------
Divide thru 3rd by 48 to get z = 2
x+3y+8z=22
0+y+7z=15
0+0+z=2
-----------------
Substitute z=2 into the 2nd and into the 1st lines:
x+3y+16=22
0+y+14=15
0+0+z=2
---------------
Solve the 2nd for y: y = 1
---------------------------------
Substitute that into the 1st to get:
x + 3*1+16=22
0 + y + 0 = 1
0 + 0 + z = 2
----------------------
solve the 1st for x: x = 3
--------------------------------
x = 3
y = 1
x = 2
=========================
Cheers,
Stan H.

RELATED QUESTIONS
Seems like such an easy question, dont know why I am stuck on it: Find the value of a... (answered by cleomenius)

A water sprinkler sprays water over a distance of 40ft, while rotating angle of... (answered by jim_thompson5910)

Please help me. We are working on probability and I am not so good with it. I am not sure (answered by checkley75)

Here is the problem: A soccer team has 16 players. How many ways can the coach choose a... (answered by rothauserc,Edwin McCravy)

a lab needs to make 100 gallons of an 18% acis solution by mixing a 12% acid solition... (answered by josmiceli)

I am stumped! I have been at this math problem for what seems like hours. I would really... (answered by gonzo,Mathtut)

I am not sure if this the right subject to put this under but... I am helping a friend... (answered by solver91311)

A driver makes a 125 mile trip from Phoenix to Tucson with the cruise control set at... (answered by Theo)

hello, I would be extremely grateful for any help or advice for this problem. It has... (answered by stanbon)