SOLUTION: I am needing help with a system of equations with 3 variables The first equation in this problem is 6q-r+2s=8 The second equation is 2q+3r-s=-9 The third equation is 4q+2r+5s= 1

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: I am needing help with a system of equations with 3 variables The first equation in this problem is 6q-r+2s=8 The second equation is 2q+3r-s=-9 The third equation is 4q+2r+5s= 1      Log On


   

Question 369070: I am needing help with a system of equations with 3 variables
The first equation in this problem is 6q-r+2s=8
The second equation is 2q+3r-s=-9
The third equation is 4q+2r+5s= 11
I am in Algebra 2 in high school and know how to use substitution and elimination.
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
1.6q-r%2B2s=8
2.2q%2B3r-s=-9
3.4q%2B2r%2B5s=+11
You use elimination to reduce from 3 equations to 2 equations.
Multiply eq. 2 by 2 and add to eq. 1,
6q-r%2B2s%2B4q%2B6r-2s=8-18
10q%2B5r=-10
4.2q%2Br=-2
Multiply eq. 2 by 5 and add to eq. 3,
4q%2B2r%2B5s%2B10q%2B15r-5s=11-45
5.14q%2B17r=-34
Multiply eq. 4 by -7 and add to eq. 5,
14q%2B17r-14q-7r=-34%2B14
10r=-20
highlight%28r=-2%29
Then work backwards and substitute,
From eq. 4,
2q-2=-2
highlight%28q=0%29
From eq. 1,
6%280%29-%28-2%29%2B2s=8
2s=6
highlight%28s=3%29