A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

.

  • This Question is Closed
  1. welshfella
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 3

    x^2 + 64 this is a like the difference of 2 squares except you have to use the imaginary number i remember that i^2 = -1 so can you fit the i values in here x^2 + 64 = ( x + ____)( x - ____)

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

    im not sure sorry

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

    ok what is the square root of 64?

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

    8

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

    ok so expand this and see if it comes back to x^2 + 64 (x + 8i)(x - 8i)

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

    it does

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

    just as in difference of 2 squares the middle terms will cancel out

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

    okayy.... so that is the first one

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

    ?

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

    (x + 8i)(x - 8i) = x^2 + 8ix - 8ix -64*-1 = x^2 + 64

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

    16x^2 + 49 handle it in the same way

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

    take square root of 16x^2 and 49

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

    (16x+7)(x+7)?

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

    No - where are the i's???

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

    (16x+7i)(x+7i)?

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

    and you take Square root of 16x^2

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

    dunno

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

    well its 4, but idk what to do with it

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

    it 4x 4x * 4x = 16x^2

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

    put 4x in each bracket

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

    (4x+7i)(4x+7i)?

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

    yes (16x + 7i)(x - 7i) would not come back to 4x^2 + 64 because the 2 terms in ix would not cancel out

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

    okay i get it

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

    next ones a bit different

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

    Oh no thats not quite right Look at your signs - doddnt forget its like difference of 2 squares

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

    (16x+7i)(x-7i)?

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

    NO its 4x !!!

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

    (4x + 7i)(4x - 7i)

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

    sorry lol i copy and pasted the wron egquation

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

    i wanted to copy then change the signs but i copied the wrong one

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

    dont know why but i can't copy and paste!

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

    weird

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

    Find the product of (x + 9i)^2. next one

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

    withe the last 3 you just expand the parentheses in the normal way (x + 9i)(x + 9i) first multiply the second bracket by x then multiply it by 9i = x(x + 9i) + 9i(x + 9i) = x^2 + 9xi + 9xi + ? can you do the last bit?

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

    ummmm

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

    9i*9i = ?

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

    sorry i really tired today

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

    81i?

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

    81* i^2 and what is i^2 equal to?

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

    -1

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

    so that is 81 * -1 = -81 x^2 + 9xi + 9xi - 81 now just add the 2 middle like terms

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

    18xi

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

    right giving x^2 + 18xi - 81

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

    is that it?

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

    Yes the 4 th one is done in exactly the same way

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

    can u just set it up (expand it) and ill take from their then you check?

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

    (x - 2i)(x - 2i) = x(x - 2i) - 2i(x - 2i)

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

    x^2-2xi-2xi-2i^2?

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

    um @welshfella

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

    right so up until the last term -2i*-2i is not -2i^2 - * - = + and 2*2 = 4

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

    x^2-2xi-2xi-4i?

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

    so -2i * -2i = ?

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

    4i?

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

    treat i as if it weer an x or a y x^x = x^2 i* i = ?

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

    4i^2

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

    * tahs x * x = x^2

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

    right + 4 i^2 = ?

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

    what do you mean by equals?

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

    i^2 = -1 so 4i^2 = ?

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

    -4 4-?

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

    -4

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

    important to remember i = sqrt(-1) so i^2 = -1

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

    k

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

    x^2-2xi-2xi-4 = x^2 - 4xi - 4

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

    so is that the answer cause it says to find the product

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

    yes the last one is more complicated because the last term in the brackets is (3x + 5i) so you could do the last part (3x + 5i)^2 first then plug it in later

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

    you can do this in the same way as the last 2 (3 + 5i)(3 + 5i) = 3(3 + 5i) + 5i(3 + 5i) ok try and do that

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

    9+15i+15i-25

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

    yea good job and we can simplify it further to 30i - 16

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

    is that the answer to the problem?

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

    No we have to plug that in to the expansion (x + (3+5i)(x + (3+5i) = x(x + (3+5i) + (3 + 5i)(x + (3+5i) = x^2 +3x + 5xi + 3x + 9 + 15i + 30i -16

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

    then simplify?

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

    yes

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

    hold on - I'm getting tired to thats wrong

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

    oookkkaaayy

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

    x(x + (3+5i) + (3 + 5i)(x + (3+5i) = x^2 + 3x + 5xi + 3x + 5xi + 30i - 16

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

    thats it now simplify that was a tricky one

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

    x^2+6x+10xi+30i-16

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

    ?

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

    looks good

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

    is that iT?

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

    yea

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

    Thanks thats it for now

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

    good I think I'll take a break lol

  85. 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.