A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • 5 years ago

what value would you add to each side to complete square x^2+18x=-8

  • This Question is Closed
  1. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    what value do you think we should add?

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

    I am not sure 9

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

    x^2+18x = x^2 + 2*9*x +0 here's the formula: a^2 + 2ab + b^2 = (a+b)^2 so, you can see a=x, b=9. you are missing b^2, to complete square you'll need b^2, which is 9^2=81 so add 81 to each side.

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

    Is That it

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

    try it, then you tell me the result.

  6. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    9 is a good number to use, but it is naked the way it is; square it and were good :)

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

    I am really confused should I square the complete equation?

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

    you can't square the whole equation. you should end up with something like this (x+a)^2+b=0 a and be can be positive or negative.

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

    except for some cases where you can just put them together nicely, of course.

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

    i had a similar problem and don't understand how to do it and how they came up with the answer it was x^2+16x=-7 the answer was 64

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

    try to put the left side into this form a^2 + 2ab + b^2. add something to make b^2, remember, you add something, you have to subtract it

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

    a=1 b=18 c=-8

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

    I know that I am having problems solving this because I can't find an example to use

  14. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    b^2 = (2ab/2a) *b

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

    ok, I'll do you this one example. x^2+16x=-7 x^2+16x+7=0 x^2+2*x*8+7=0 compare this to a^2 + 2*a*b + b^2=(a+b)^2 you can see clearly that a=x b=8 so if b=8, b^2=64, you need to add 64, but you add 64, you need to subtract 64 then equation becomes x^2 + 2*x*8 + 64 - 64 + 7=0 (a+8)^2 + (-64+7) = 0 (a+8)^2 - 57 = 0 there's the answer

  16. amistre64
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    18/2(1) = 9*9 = 81

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

    (a+9)^2-73=0 So I would add 81 to both sides

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

    ??? I dont get it.

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

    x^2+18x=-8 x^2+2*x*9+81-81+8=0 (a+9)^2+(-81+8)=0 (a+9)^2-73=0 I would add 81 to both sides

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

    exactly. that's right

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

    Thank you now I have an example to go by

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

    anytime

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

    5x^2-3=0 no solution is that correct?

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

    thank you got to go let me know if that is right

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

    you mean to complete square, no, but there are solutions, add 3 to both sides, then divide both sides by 5, you'll get x^2=3/5=(sqrt(3/5))^2=(-sqrt(3/5))^2 so x=sqrt(3/5) or x=-sqrt(3/5)

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

    thanks i figured it out square root property

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

    ah that's good, good luck with ur maths

  28. 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.