Posted by **Mary Ann** on Monday, October 7, 2013 at 10:24am.

I need help I don't know how to solve this system

Solve the following system. Show all your work

3x-2y+2z= 30

-x+3y-4z= -33

2x-4y+3z= 42

- Algebra, help needed -
**Steve**, Monday, October 7, 2013 at 12:03pm
what makes it especially difficult? You must have solved similar systems already.

2(1st)+(2nd) and 3(1st)-2(3rd):

5x - y = 27

5x + 2y = 6

Now it gets easier:

3y = -21

y = -7

so,

x = 4

z = 2

- Algebra, help needed -
**Mary Ann**, Monday, October 7, 2013 at 12:19pm
every time i try adding two equations that could make it simpler ex; by adding and crossing out variables. i just could never get it right and still have those three same variables thx for the help

- Algebra, help needed -
**Steve**, Monday, October 7, 2013 at 12:27pm
Yeah, it takes a bit of practice. Look for LCMs to get rid of stuff. In this case, since 3*2=6, we had to take 3 times the 1st to get 6 and 2 times the 3rd to get 6.

Usually the errors come in watching the other coefficients. In the beginning, it helps to write everything down so details don't get lost.

- Algebra, help needed -
**kendra**, Monday, October 7, 2013 at 6:31pm
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