# Homework Help: Simultaneous Equations

1. Jul 27, 2009

### Stripe

1. The problem statement, all variables and given/known data
Find a,b,c,z
2a+b+2c=z
a+2b+c=4
a+b+2c=3

2. The attempt at a solution
Ok so i've tried multiplying all lines by 2 so you may possibly cancel out 2a, but not sure where to go after i multiplied everything.

Then i tried to just cancel one equation and then another one e.g

4a+5b+4c=10
4a+4b+8c=12

B-4c=-2

But not sure.

I would really like an explanation on how to actually do it rather than the answer.

2. Jul 27, 2009

### cheff3r

the question has given 4 variables and only 3 equations so you can not find a,b,c,z what you may be able to do is find a,b,c in terms of z and a constant.

to do this continue wih the subsitition of one equation into another treating z as a constant

not sure how you got 4a+5b+4c=10, 4a+4b+8c=12

but try subsituting
a+2b+c=4
a+b+2c=3 canceling the 'a'
and do the same with
2a+b+2c=z
a+2b+c=4
then you will have 2 equations and two unkowns, i'm sure you can see where to go with that

3. Jul 28, 2009

### Stripe

Ok thanks for the help i've figured it out. i appreciate the help :D