## thcsbabygirl1224 one year ago help me please 4x+y+5z=-9 x-4y-2x+-2 2x+3y-2z=21

1. anonymous

Use matrix

2. thcsbabygirl1224

what its a system of equations solving for 3 variables so im lost

3. thcsbabygirl1224

@hartnn

4. thcsbabygirl1224

@LazyBoy @hba

5. thcsbabygirl1224

@chainedecho

6. Loser66

The second equation should be x-4y-2z =-2, right?

7. thcsbabygirl1224

yes

8. Loser66

take the third one subtract the second one, what do you get? that is (3) -(2) =??

9. thcsbabygirl1224

i am trying to get rid of the x in all 3 equations so i have to set them to 0 im lost on the work

10. Loser66

YOu lost on your way, give it a try on my way, ok? Again (equation 3 )-(equation 2) is??? You should work on it, I am guiding you only.

11. thcsbabygirl1224

@kal1921 what is the matrics

12. Loser66

Good luck.

13. thcsbabygirl1224

ok i have now -2x-4y-2z=-4 2x+3y-2z=21

14. thcsbabygirl1224

@Michele_Laino

15. Michele_Laino

here, you have a system of two equations, with three unknows. We can rewrite it as below: $\left\{ \begin{gathered} 2x + 4y = 4 - 2z \hfill \\ 2x + 3y = 21 + 2z \hfill \\ \end{gathered} \right.$ which can, easily solved for x, and y as functions of z. Please try

16. thcsbabygirl1224

You get 7y-4z=16