## AonZ 2 years ago Simutaneosly solve x-5y-z=13 2x+y+z=0 -3x+y+2z=11

1. AonZ

I know how to solve 2 simutaneous equations but no idea about 3

2. AonZ

i rather the elimination method :P

3. hartnn

ok, so if i help you get 2 equations in x and y only , will you be able to solve the rest ? 1) Add 1st and 2nd equation, what u get ?

4. AonZ

3x-4y=13

5. AonZ

i just need the steps in which to complete it i think

6. hartnn

now multiply 1st equation by 2

7. AonZ

6x-8y=26

8. hartnn

:O how ?

9. AonZ

2x-10y-2z=26

10. hartnn

now add it with 3rd equation.....

11. AonZ

-x-9y=37 Btw does it matter if you add the 2nd to the 3rd eqution instead of 1st to 3rd?

12. hartnn

if you add 2nd and 3rd equation, you could not have eliminated 'z'

13. hartnn

now can you find 'x' and 'y' ?

14. AonZ

y=-4?

15. AonZ

x=-1

16. hartnn

yes.

17. hartnn

now can u find z ?

18. AonZ

mhm... I sub x and y into the 1,2,3 equation?

19. AonZ

ok z =6 thank you

20. hartnn

yes, correct :) ask if any doubts.