A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • 5 years ago

Solve. 2x2 + 20x = –38 a. –5 ± √14 b. –5 ± √51 c. –5 ± √6 d. –5 ± √13

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

    c as usual. why is it always c?

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

    can u show me how, though, im trying hard to remember but its not coming to me...

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

    ok first off each term has a factor of 2, so we can make our life easier by writing \[x^2+10x=-19\]

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

    then we can write the left hand side as a perfect square , by taking half of 10, which is 5, squaring and adding it to both sides to get \[(x+5)^2=-19+25=6\]

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

    then take the square root, don't forget the plus and minus \[x+5=\pm\sqrt{6}\] then subtract 5 \[x=-5\pm\sqrt{6}\]

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

    oh i get it now, and this is for all problems like this?

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

    yes you can always use this method. if you like you could write \[x^2+10x+19=0\] and then use the quadratic formula, but that would be more work because you would have a denominator, and then you would have to simplify the radical, factor and cancel to get the answer you see above

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

    oh okay, thanks. can u also help me with http://openstudy.com/study?F295750376716BE3I5S=_#/updates/4f178119e4b0aeb795f57dc2

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

    if the coefficient of the "middle term" is even, then it is much easier to complete the square

  10. 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.