## Sophia.13 Group Title 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 Group Title

The two methods are elimination and substitution.

2. Sophia.13 Group Title

There is also graphing

3. skullpatrol Group Title

What have you tried?

4. Sophia.13 Group Title

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

5. skullpatrol Group Title

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

6. Sophia.13 Group Title

Ok

7. skullpatrol Group Title

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

8. Sophia.13 Group Title

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

9. skullpatrol Group Title

No.

10. Sophia.13 Group Title

oh

11. Sophia.13 Group Title

well, how do i do it?

12. Azteck Group Title

Do it simultaneously.

13. skullpatrol Group Title

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

14. skullpatrol Group Title

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

15. Azteck Group Title

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

16. Azteck Group Title

$-3y+18y=-30$ 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 Group Title

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