A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

Republican31

  • one year ago

If g(x) = x2 – 2x, find the value of g(-3) + 1. Is 8 = 4 + 4 correct?

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

    If you mean \[\Large g(x)=x^2-2x\] then \[\Large g(-3)+1=(-3)^{2}-2(-3)+1=9+6+1=16\]

  2. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Yes sorry that is what I meant. I didn't notice that little formatting error.

  3. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    But it's -3 + 1, meaning -2, right?

  4. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Yep

  5. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    So does that mean it is 8 or 16?

  6. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Wait a minute.

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

    If you mean \[g(-3+1)\] then is 8, but if is \[g(-3)+1\] then is 16

  8. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Ugh...

  9. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    \[g(\color{red}{-3})+1=(\color{red}{-3})^{2}-2(\color{red}{-3})+1=\color{red}{9}+6+1=16\]

  10. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Which part is confusing you exactly?

  11. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    So 16 = 9+6+1 is correct?

  12. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Well, when you add 9 + 6 + 1, what do you get?

  13. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    I just don't understand how (-3) + 1 is any different from (-3 + 1) unless it's because of the g in front. I don't like these functions.

  14. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Well, think about \(x=-3\) , does that also mean \(x=-3+1\)?

  15. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Your question is basically saying that you have a function \(g(x) = x^2-2x\), now when \(x=-3\) you replace \(-3\) wherever you see \(x\) in the function.

  16. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    N...No?

  17. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Okay. And then the +1? I see it come in at -2x, but not for the x^2.

  18. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Ontop of that, you're adding a `+1` to your function's value, therefore \(g(x)+1\) is what you're solving for.

  19. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Do you see it now?

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

    the +1 you can add up at the end

  21. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Okay but why isn't it + 2 for both times that x was used?

  22. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    +2?

  23. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Okay let's try a different question. Like to try a different one? This time you will solve it.

  24. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    I'm sorry I just am having trouble understanding. What I'm wondering is if there was x2 - 2x, then doesn't that mean (-3) + 1 was used twice, so there should be a + 1 from each time x was used in the equation

  25. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Alright.

  26. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Let's take \(f(x) = x^3+3x+5\) and we're finding \(f(-5)+3\)

  27. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Okay.

  28. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    So what is the first step you would do?

  29. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    = 125 - 15 + 5?

  30. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Let's check

  31. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Sorry -125

  32. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    \[f(\color{blue}{-5}) = (\color{blue}{-5})^3 +3(\color{blue}{-5})+5\]

  33. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Did you get -125 - 15 + 5?

  34. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Ya. I saw my mistake of having 125 instead of -125.

  35. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Alright :D and that gives you -135 correct?

  36. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    yes

  37. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Now that we've solved that portion, we're going to add \(+3\) to our answer. This is because we are looking for \(f(-5)\color{blue}{+3}\) and not just \(f(-5)\)

  38. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    So then what is -135 + 3?

  39. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Alright but I just was wondering why it isn't (-5) + 3^2. And it's 132.

  40. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    *-132

  41. Jhannybean
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    To my knowledge, we're changing and shifting a function by changing the x value. you `might` be over thinking it!

  42. Republican31
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    Alright. Thank you so much for all your help!

  43. 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.