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careless850

  • 3 years ago

If someone could help me with these last few problems, it would be nice. Check all polynomials that are perfect square trinomials: A) 49x^2 − 8x + 16 B) 4a^2 − 20a + 25 C) 25b^2 − 5b + 10 D) 16x^2 − 8x + 1

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  1. careless850
    • 3 years ago
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    Anyone? :)

  2. careless850
    • 3 years ago
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    Which ones are perfect square trinomials?

  3. megan1124
    • 3 years ago
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    a is do you know how i figured that out?

  4. careless850
    • 3 years ago
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    No, I don't.

  5. megan1124
    • 3 years ago
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    have you learned foil?

  6. Diyadiya
    • 3 years ago
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    No A is not the right answer!

  7. careless850
    • 3 years ago
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    Diya, there is more than one I can choose for the right answer. How come A isn't one of them?

  8. megan1124
    • 3 years ago
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    |dw:1338062447129:dw| that is y it is

  9. Diyadiya
    • 3 years ago
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    If \( ax^2+bx+c \) is a perfect square trinomial then the discriminant will be zero. Do you know to find the discriminant? \( D= b^2- 4ac =0\)

  10. careless850
    • 3 years ago
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    I'm so confused...

  11. megan1124
    • 3 years ago
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    thats not how you do that

  12. Diyadiya
    • 3 years ago
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    @megan1124 (7x-4)(7x-4) = 49x^2-56x+16

  13. megan1124
    • 3 years ago
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    noo it equals a

  14. careless850
    • 3 years ago
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    um.. Can someone just show me how to do these or.. if you are going to argue.. just give me a hint to the right answers please...

  15. megan1124
    • 3 years ago
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    are you in algebra 1?

  16. careless850
    • 3 years ago
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    Yep

  17. careless850
    • 3 years ago
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    for the 3rd time.

  18. Diyadiya
    • 3 years ago
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    @careless850 Lets check the second option \( 4a^2 − 20a + 25 \) this is of the form \( ax^2+ bx + c \) Now find \(b^2-4ac \) \(b^2-4ac = (-20)^2- 4*4*25= 400-400 = 0 \) Now verify if your answer is right \( 4a^2 − 20a + 25 = (5-2a)(5-2a) =(5-2a)^2 \)

  19. megan1124
    • 3 years ago
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    ok thanks its and b :) because you can divide the first one and last one by a number and get the same number you divided by and get a whole number

  20. careless850
    • 3 years ago
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    O.o what? So is one of the answers A or is one B?

  21. megan1124
    • 3 years ago
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    the 2 answers are a and b because if you factor them you don't get more that 2 numbers like the one i showed you above earlier

  22. careless850
    • 3 years ago
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    So C and D aren't?

  23. Diyadiya
    • 3 years ago
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    \( 49x^2 − 8x + 16 \) Find \(b^2 -4ac \) b=-8 , a=49 , c=16 \(b^2 -4ac = (-8)^2 - 4(49)(16) = -3120 \) So option A is not the right answer Can you check for C now?

  24. careless850
    • 3 years ago
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    Diya, A isn't right? So the only right answer is B?

  25. Diyadiya
    • 3 years ago
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    A isn't Right! i just showed you why.. B is right But you have to check the others too

  26. megan1124
    • 3 years ago
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    you can have more than one right answer right? if so its a and b

  27. Diyadiya
    • 3 years ago
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    @megan1124 A is not the right answer Can you tell me what is (7x-4)(7x-4) ??

  28. megan1124
    • 3 years ago
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    its a

  29. Diyadiya
    • 3 years ago
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    Nope, try to solve it and see

  30. careless850
    • 3 years ago
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    There is multiple answers that can be right.

  31. Diyadiya
    • 3 years ago
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    Can you find the discriminant of C & D ? \( D= b^2-4ac \)

  32. careless850
    • 3 years ago
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    I don't know what the disciminant is.

  33. Diyadiya
    • 3 years ago
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    \( 25b^2 − 5b + 10\) this is of the form \( ax^2 + bx +c \) |dw:1338063436660:dw| so a =25 b=-5 c=10 Now find Dicriminant \( D =b^2-4*a*c\) Can you do that?

  34. Diyadiya
    • 3 years ago
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    Just plug in the values of a ,b & c in the equation \(b^2 - 4ac \) can you ?

  35. Diyadiya
    • 3 years ago
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    @careless850 Pls tell me if you're stuck somewhere

  36. Diyadiya
    • 3 years ago
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    is it equal to zero or some other number ?

  37. careless850
    • 3 years ago
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    I'm still confused..

  38. Diyadiya
    • 3 years ago
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    where are you stuck ? did you find b^2 -4ac?

  39. careless850
    • 3 years ago
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    No.

  40. Diyadiya
    • 3 years ago
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    Find it :) & check if its equal to zero

  41. careless850
    • 3 years ago
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    How do I find it?

  42. careless850
    • 3 years ago
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    ......

  43. Diyadiya
    • 3 years ago
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    25b^2 − 5b + 10 Given : a =25 b=-5 c=10 b^2 - 4ac

  44. Diyadiya
    • 3 years ago
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    (-5)^2 - 4* 25 * 10 is it equal to zero?

  45. careless850
    • 3 years ago
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    no

  46. Diyadiya
    • 3 years ago
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    so its not a perfect square trinomial Now do the last one D) 16x^2 − 8x + 1 Can you tell me what is a ,b & c here?

  47. careless850
    • 3 years ago
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    a is 16

  48. Diyadiya
    • 3 years ago
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    yes b & c?

  49. careless850
    • 3 years ago
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    -8 is b and 1 is c.

  50. Diyadiya
    • 3 years ago
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    Right!!!!!!! Now Find the discriminant How do you find it?

  51. careless850
    • 3 years ago
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    So I would do this.. -> -8^2 -4*16*1.

  52. Diyadiya
    • 3 years ago
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    Yessss good work :)

  53. careless850
    • 3 years ago
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    how to solve that, I don't know, but that's the problem.. lol

  54. Diyadiya
    • 3 years ago
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    \( (8)^2 - 4 \times 16 \times 1 \) What is \( 8^2 \) ?

  55. careless850
    • 3 years ago
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    64

  56. careless850
    • 3 years ago
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    64-64 = 0

  57. careless850
    • 3 years ago
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    So it's a PST

  58. Diyadiya
    • 3 years ago
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    Yess!! so its a perfect square trinomial :) You can verify by factoring ^_^

  59. careless850
    • 3 years ago
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    I see. Pretty easy now I guess. So the only ones that are perfect square trinomials are B and D?

  60. careless850
    • 3 years ago
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    Can you help me with another?

  61. Diyadiya
    • 3 years ago
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    Yes, If you factorise 16x^2 − 8x + 1 you'll get (1-4x)(1-4x) = (1-4x)^2 Post it as a new question :)

  62. Diyadiya
    • 3 years ago
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    Yes its B & D

  63. careless850
    • 3 years ago
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    Thank you. :))

  64. Diyadiya
    • 3 years ago
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    Np :)

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