A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • 5 years ago

The objective is to solve system problems of equations by the addition method ( no multiplying required) how would you solve this : 2x+y=3 -2x+5y=-9 have solve for x and y to plot on graph.

  • This Question is Closed
  1. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    2x + y = 3 -2x + 5y = -9 If you add straight down you get 6y = -6 divide by 6 and you get y = -1 Then you need to substitute the y = -1 into either one of the original equations. I will put it into the first one. 2x -1 = 3 add 1 to both sides 2x = 4 divide by two x = 2 So x = 2 and y = -1

  2. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    How would you solve for x and y to plot on graph for this equation: 7x-y=12 -3y+7x+8 ?

  3. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Do you want to plot this on a graph to solve this?

  4. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    yes, It's just like the previous question that I asked.

  5. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Check your second equation. there is something wrong with it. Then I will help you solve it.

  6. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    -3=7x+8

  7. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Is there no y in that equation?

  8. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I'm sorry, it's -3y=7x+8

  9. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    7x - y = 12 and -3y = 7x + 8 (First thing is to get the x's and y's on the same side.

  10. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    7x - y = 12 -7x - 3y = 8 (I subtracted 7x from both sides)

  11. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    7x - y = 12 -7x - 3y = 8 (Notice if you add straight down your x's are gone) -4y = 20 (Added the two equations together) y = -5 (Divide both sides by -4) Put y = -5 into 7x - y = 12 7x - (-5) = 12 7x + 5 = 12 7x = 7 x = 1 So... x = 1 and y = -5

  12. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    same thing here: y=3x+13 2x=y-9 solve for x and y and plot on graph.

  13. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Put the x's and y's on the same side with the number on the other side... What do you get?

  14. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Is it 5x and 2y=4?

  15. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    If you take y = 3x + 13 How do you get the 3x on the side with the y?

  16. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    do you sub. 3x to move it?

  17. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Yes... so you get -3x + y = 13 Now the second equation 2x = y - 9 how do you get the y over with the 2x?

  18. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    subtract y to move it

  19. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Yes.. so now you have 2x - y = -9 Now write both of those equations over each other.

  20. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    -3x + y = 13 2x - y = -9 And you get this ... ok?

  21. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ok, then what do I do I know that I sub. and get -x=4 is this correct?

  22. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Well... you actually add but yes you get -x = 4 so to solve for x when x is negative you simply take the opposite of both sides. So the opposite of "negative x is positive x" and the opposite of "positive 4 is negative 4" x = -4

  23. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Now we are going to substitute x = - 4 into one of the equations. Let's use the y = 3x + 13 so.. y = 3(-4) + 13 y = -12 + 13 y = 1 So x = -4 and y = 1

  24. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    last problem: 4x + 12 = -7y -y +12= 4x solve for x and y to plot on graph.

  25. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Get x's and y's on the same side with the number on the other. What would you get for 4x + 12 = -7y

  26. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    4x-7y+12

  27. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Well you need an = sign in this problem... Bring the -7y over to the 4x and take the 12 to to the other side. What do you get?

  28. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I meant 4x-7y=12

  29. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    If it is -7y on the right side you add 7y and it becomes + 7y on the left side. If it is + 12 on the left side you - 12 from both sides and it becomes -12 on the right side.

  30. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    So you get 4x + 7y = -12 Try the 2nd equation -y + 12 = 4x

  31. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    -4x+y=-12

  32. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Close.. You -4x which is correct, you - 12 which is correct.. but if you look at the 2nd equation is says "-y" on the left side so it needs to stay "-y" on the left side. -4x - y = -12 Now put those two over each other.. add... and tell me what you get.

  33. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    y=-4

  34. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    You should have gotten -6y = -24 Then you divide by -6 and you get y = 4 Now put y = 4 into one of the equations... Let's pick 4x + 12 = -7y

  35. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    x=4

  36. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    You should have gotten 4x + 12 = -7(4) 4x + 12 = -28 subtract 12 from both sides 4x = -40 divide by 4 x = -10 So the answers are x = -10 and y = 4

  37. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    that can't be right because the puzzle I'm doing leaves me with the letter d which is x=4 and y=-4 to spell out a sudden debt payoff.

  38. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    OK Let me do it again.

  39. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    4x + 12 = -7y -y +12= 4x 4x + 7y = -12 -4x - y = -12 4x + 7y = -12 -4x - y = -12 6y = -24 y = -4 4x + 12 = -7(-4) 4x + 12 = 28 4x = 16 x = 4 You are correct x = 4, y = -4 Look thru my answer here... This is important you know how to do these because they are going to get harder on the next lesson and if you don't get this well, you won't get the next step. Study hard.... it pays off :-)

  40. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Thanks a lot I've got another sheet to do later maybe I'll get you again to help me. Is there a way I can ask for you personally?

  41. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Sure.. you can email me at amcbeth328@gmail.com

  42. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    You were a great help. I'm not that great at math. I have a 62 average and my teacher told me that I have to get at least a 78 this 4 weeks or I will have to go to recovery school this summer.

  43. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I can tell you are weak... I would be glad to help you as long as you want to learn and not just want answers, because in the long run, you will get deeper and deeper into not getting it and it will hurt you in the long run.

  44. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I'm not looking for answers. I just don't understand how to do the problems sometimes and my teacher is so busy she doesn't have time to be one on one with to explain how to do them. I have always been weak in math but this year is really kicking me in the butt. I would go to tutoring but we don't have a car and no one in school will give me a ride home so therefore I'm kind of stuck trying to figure this stuff out on my own. It's been a long time since my parents were in school so they can't help me much.

  45. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Write me anytime.

  46. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.