anonymous 5 years ago how do you graph this system of equations x-y=3 x-2y=3

1. anonymous

Easy you first find what y and x equal by using elimination

2. anonymous

Do you know how to do elimination? (:

3. anonymous

yes, i think..

4. anonymous

You need me to clarify? (:

5. anonymous

6. anonymous

Haha yea sure (: Okay so you have to firsy see if anything can cancel out

7. anonymous

first*

8. anonymous

As you can see nothing cancels out. Since your graphing it wont matter which one you start with. So then you have to think what do i have to multiply so that either the x or y variables will be crossed out

9. anonymous

I would try to cross the Y variable out first. So you Have to Multiply the whole equation (x - y = 3) by 2 so that the y will cross out so then

10. anonymous

I take that back you would multiply by -2

11. anonymous

So that you would be able to cross them out ( negative & positive)

12. anonymous

Okay so then you would get 2x + 2y = 6

13. anonymous

If you set them up like so 2x + 2y = 6 x - 2y = 3 You would see that the 2y does no indeed, cancel out. So then you'd get

14. anonymous

does* not does not lol

15. anonymous

So then if you add the two equations you get 3x = 9 x = 3 Then to solve for Y You would have

16. anonymous

$\text{Psst, 'graph' \not= 'solve'}$

17. anonymous

Haha i know. But this is also a good way to do it. Okay so then you would plug the 3 in for x

18. anonymous

-3?

19. anonymous

No offence, but this is a very long way to do it.

20. anonymous

Its the way i was taught....

21. anonymous

Why dont YOU help him then :P

22. anonymous

i really appreciate the help

23. anonymous

lol

24. anonymous

is y= -3?

25. anonymous

Yes, im pretty sure (: Go ahead and show me how you got that and i will tell you if its correct. Btw sorry Newton I just have an immense respect for my teachers ^_^ Even though most the time I dont like them

26. anonymous

you put 3 in for x in one of the equations?

27. anonymous

Your teachers taught you that is how to figure out how to graph an equation?

28. anonymous

No they taught me to find the variables and then graph... lol easy peasy..

29. anonymous

The steps just seem long, after you did it a lot its not that hard :P

30. anonymous

do*

31. toxicsugar22

hi can anyone here help me after u help her

32. anonymous

Yes dark lol.. (: Okay and then you do y-intercept and slope to graph (:

33. anonymous

$x-y = 3 \implies y = x-3$ $x-2y = 3 \implies y = \frac{x-3}{2}$ You (should be able to!) can graph these right form here, as they are in the form y = mx + c. But setting x = 0, y = 0 to find the intercepts may help.

34. anonymous

im a guy* thnak you! lol

35. anonymous

x - slope and y = y intercept

36. anonymous

37. toxicsugar22

oh srry can someone help me after him

38. anonymous

toxicsugar said her*........ anyways.................thank you very much!

39. anonymous

Haha oh.. ^_^ blonde moment... And yes good process. That's just the way i was taught ^_^