A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • 5 years ago

I am in Introductory Algebra and I am unsure on how to graph a linear equation. Can someone please help me. The equation is -7x-y=2

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

    Can you graph an equation written in the form y = mx + b?

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

    From what I was reading in my book that is the formula that helps give the answer but I dont know if my answer is right.

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

    Well it's currently tough to graph on OpenStudy, but the first thing to do with the above equation is to get it in that form, y = mx + b. Have you already done that/do you know how?

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

    That is where I am having the problem. I don't know how to do that correctly.

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

    Ok. So the key here is that we want y to be alone, and we want it to be positive. I generally like to start by making y positive. Can you move the y in -7x - 7 = 2 to the right side of the equation?

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

    -7x - y = 2, sorry.

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

    I know that it has to be positive and I think if I add 7x to both sides it might help but again I am unsure about that answer

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

    That's actually one way to go about it. So let's try that: -7x - y = 2 -7x + 7x - y = 2 + 7x The -7x + 7x cancels out, so we have: -y = 2 + 7x We can reorder the right side so we have: -y = 7x + 2 Now, our model is y = mx + b, so there's just one thing still wrong: the - on the left side. Do you have an idea for how to get rid of it?

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

    I do believe that you would have to divide by -1 on both sides

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

    Right -- dividing or multiplying would do the same thing. So you have: (-1)(-y) = (-1)(7x + 2) y = (-1)(7x) + (-1)(2) y = -7x + (-2) y = -7x - 2

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

    So now we have y = mx + b, where m = -7 and b = -2.

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

    and those are the points that I would graph correct?

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

    Not quite. They tell you what the graph will look like. In particular, -7 is the slope, which indicates rise over run. So that means if your graph starts at (0, 0), it will `rise' -7 (or drop 7) on the y axis for every 1 x value. -2 is the y-intercept, which means that when x is 0, y will be -2. So you have the starting point: (0, -2), and you have the slope, which tells you that at x = 1, y = -9, which means the second point is (1, -9). And then you can draw a line between the two. Make sense?

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

    Thank you so much that really helps me out. It makes a lot of sense now that I can understand it.

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

    Awesome! Good to hear!

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

    finding the slope of a line would be taking two points of the graph and using y=mx+b?

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

    You would use the slope formula. Assuming you have two points (x1,y1) and (x2,y2). The slope m = (y2-y1)/(x2-x1).

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

    actually the equation is x=3

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

    The slope in the case of x = 3 is what we call `undefined'. Basically, rise over run gives us a number divided by zero (actually infinity divided by zero), because x = 3 means a line going straight up and down at x = 3.

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

    Thank you I did not know that. My instructor did not explain that too well.

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

    No problem!

  22. 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.