Quantcast

A community for students. Sign up today!

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

EmmaH

  • one year ago

PLEASE HELKP ME IM BEHIND PLEASE EXPLAIN STEPS AND I WILL GIVE YOU A MEDAL. Factor the trinomial: 4x^2 - 8x - 5 (2x + 1)(2x - 5) (4x + 1)(x - 5) (4x - 5)(x + 1) prime

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

    |dw:1360095374158:dw|

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

    I am going to teach you a method called slide and divide take the 1st number and slide it to the back by multiplying it to the last number

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

    so -20

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

    |dw:1360095443097:dw|

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

    we know x times x is x to the second power we are using 10 and 2 because 10 times 2 is 20 but we need to subtract them to get 8 the minus sign in front of 20 tells us to subtract those two numbers

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

    |dw:1360095532927:dw|

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

    |dw:1360095517633:dw| what happened there?

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

    +2-10 gives us -8 we need -8x

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

    last step is to divid the number back in

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

    |dw:1360095575598:dw|

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

    because 1/2 is a decimal we will now take the 2 and move it in front of x and drop the 1

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

    |dw:1360095620919:dw|we are done

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

    hey please slow down

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

    you can read through each step until you learn the pattern

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

    |dw:1360095653585:dw| you lost me here

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

    i dont understand what you did

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

    |dw:1360095676993:dw|you have to list all of the products of 20

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

    the sign in front of 20 tells you to subtract them, you are looking for the middle term

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

    |dw:1360095746738:dw|

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

    |dw:1360095763812:dw|use 2 and 10

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

    but that would be positive 20

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

    |dw:1360095780117:dw|these are your sign choices

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

    do the signs separate

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

    |dw:1360095836253:dw|

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

    ok look i found -2, and 10 to be the correct factors all i wanted to know was how to inser that into the equation and solve

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

    |dw:1360095897773:dw|

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

    2 must be positive and 10 must be negative

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

    |dw:1360095963415:dw|

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

    ok im sorry i made a huge mistaje when writting this i didnt use the ^

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

    look at the prob again

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

    does not change my answer since I did use the correct notation

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

    can you please not use the drawing i cant read it or understand it..im sorry im just so confused at how you got your answer and i understand if you want to just give up on me..

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

    sorry need to go, repost your problem someone will come help you

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

    alright

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

    4x^2 - 8x - 5 Ok so I'll try to explain this the way I understand it. Usually to factor you have to find 2 numbers that multiply to equal the last number, and add up to equal the number part of the middle. I'll just use \[ax ^{2}+bx+c\] as an example equation. So you have to find 2 numbers that multiply to get c, and add up to get b. Then you would usually take those 2 numbers and use it to factor and get (x+?)(x+?). But since there is a number for a that is not 1 in your equation, it's a little different. First, multiply the first and last numbers 4 and -5 (a and c in the example equation). You get -20. So try to find 2 number that are factors of -20 and add up to equal 8. Just start to list the factors off on paper or in your head. Remember to include the negatives. -1, 20 1, -20 -2, 10 2, -10 These add up to equal -8 Then put 2 and -10 to separate the middle part of the equation. \[4x ^{2}+2x-10x-5\]Then group the equation into 2 separate parts. \[(4x ^{2}+2x)+(-10x-5)\]Then you take out any common factors from the parentheses.\[2x(2x+1)-5(2x+1)\]And then group together the parts you took out, which are the 2x and -5.\[(2x-5)(2x+1)\]It becomes this because 2x+1 are the same. There's your answer. Hope this helps!

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

    yes rose is showing the method known as factor by grouping. Both methods are correct

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

    • Attachments:

Ask your own question

Ask a Question
Find more explanations on OpenStudy

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.