## Sophia.13 Solve using two differemt methods. Explain which method you found to be more efficient. a. 3x-9y=3 6x - 3y= -24 one year ago one year ago

1. wio

The two methods are elimination and substitution.

2. Sophia.13

There is also graphing

3. skullpatrol

What have you tried?

4. Sophia.13

Nothing yet, i know how to do elimination. But i dont know how to substitution or graphing.

5. skullpatrol

Use elimination and find the answer first. All the methods should give the same answer, right?

6. Sophia.13

Ok

7. skullpatrol

$$3x-9y=3$$ $$6x - 3y= -24$$

8. Sophia.13

I got 3x-6y= -27 but i dont think its rigth is it?

9. skullpatrol

No.

10. Sophia.13

oh

11. Sophia.13

well, how do i do it?

12. Azteck

Do it simultaneously.

13. skullpatrol

You said you know how to use elimination. Try multiplying the first equation by $$-2$$ and add it to the second equation...

14. skullpatrol

$$(3x-9y=3) (-2)$$ 6x - 3y= -24

15. Azteck

$3x-9y=3 [1]$ $6x - 3y= -24 [2]$ $2\times [1]$ $6x-18y=6 [3]$ $[2]-[3]$ $(6x - 3y) - (6x-18y)= (-24)-(6)$

16. Azteck

$-3y+18y=-30$ The x's cancel out. Now you can solve for y. Once you solve for y, you can then substitute the y component that you just found, into any one of the equations above to find your x-value.

17. Azteck

If you need further assistance, I will be happy to elaborate it in more simple terms.