# Thread: Solving system of equations with 3 variables.

1. ## Solving system of equations with 3 variables.

The question is:

16x+12y+4z=364
4x+37+4z=100

What is the value of 20x+15y?

In school, whenever I did problems with 3 variables, there were always 3 equations given. is this possible to solve?

2. ## Re: Solving system of equations with 3 variables help!

Is the second equation as written, or should the middle term be 37y?

3. ## Re: Solving system of equations with 3 variables help!

Note how the $4z$ term appears in both equations... do you think you may be able to remove it?

4. ## Re: Solving system of equations with 3 variables help!

Originally Posted by Prove It
Is the second equation as written, or should the middle term be 37y?

OH, RIGHT, it is 37y! sorry!

and yes, I've tried to remove the 4z by combination, but I don't know what to do from there!

5. ## Re: Solving system of equations with 3 variables help!

Try to make other combinations until you've an equation in one variable.

6. ## Re: Solving system of equations with 3 variables help!

hi guys i got 455.

7. ## Re: Solving system of equations with 3 variables.

Originally Posted by cindyli319
The question is:

16x+12y+4z=364
4x+37+4z=100

What is the value of 20x+15y?

In school, whenever I did problems with 3 variables, there were always 3 equations given. is this possible to solve?
It seems more likely that the 37 should be 3y.

You then have:
16x+12y+4z=364
-4x -3y -4z=-100

Add the equations to get 12x+9y. Then multiply be 5/3 .