Posted by **Matt** on Tuesday, September 20, 2011 at 7:59pm.

Right now we're doing systems of Linear Equations in Three Variables. It says to solve the following system:

x - y + 3z = 4

x + 2y - z = -3

4x + 3y + 2z = -5

Whatever I try with this problem (and the others like it) it comes out wrong. I've had about one success.

And Is there a certain order you're supposed to solve them in? Or does that not make a difference?

- Algebra II -
**Reiny**, Tuesday, September 20, 2011 at 8:32pm
I will assume you are using elimination, although there are several other methods.

In elimination, you first have to decide which variable you want to eliminate. Usually that is determined by choosing the simplest coefficients, in this case I would go for z

1st: x-y + 3z = 4

2nd times 3: 3x + 6y - 3z = -9

add them 4x + 5y = -5 (#4)

2nd times 2: 2x + 4y - 2z = -6

3rd: 4x + 3y + 2z = -5

add them 6x + 7y = -11 (#5)

#4 times 3 : 12x + 15y = -15

#5 times 2: 12x + 14y = -22

subtract them

y = 7

back into #4 : 4x + 35 = -5

4x = -40

x = -10

back into #1 : -10 - 7 + 3z = 4

3z = 21

z = 7

x = -10 , y = 7, z = 7

## Answer This Question

## Related Questions

- algebra - I do not know how to solve the following systems of linear equations ...
- algebra 2 - how do u solve a system of linear equations in three variables? for ...
- algebra - Can anyone help me to understand algebra? Right now I am working on ...
- Algebra 2 - Solving systems of linear equations in three variables. Ok so i dont...
- Alg 2 - Today we learned how to solve systems of equations with 3 variables, ...
- Algebra - Can you please give an example step by step of how to solve a system ...
- Algebra - Solving systems of linear equations in 3 variables... 1) 3x-2y+2z=1 2...
- Algebra - What are 3 ways to solve system of linear equations in two variables?
- algebra - systems of linear equations in 3 variables 1/3x-2/3y+z=0 1/2x-3/4y+z=1...
- Algebra - Find the number of the solutions to each system. a. 4x-y+1=0 4x-y+3=0 ...

More Related Questions