MATH TIME!

Discussion in 'User Topics' started by Mr.Lame, Jan 9, 2018.

  1. MarkFL

    MarkFL Guest

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    If you're suppose to evaluate the given quadratic expression at t = 2, then 228 is correct:

    16t^2 + 80t + 4 = 4(4t^2 + 20t + 1) = 4(4(2)^2 + 20(2) + 1) = 4(16 + 40 + 1) = 4(57) = 4(50 + 7) = 200 + 28 = 228

    You would only need to use the quadratic formula (or you could complete the square), if you were asked to solve the equation:

    16t^2 + 80t + 4 = 0
     
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  2. Mr.Lame

    Mr.Lame Veteran

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    The answer says it should be 100. I'll type it out once I drop my little one off at school.

    Thanks Mark :D :D
     
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  3. MarkFL

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    In order for the expression to equal 100, we can find the correct t by setting:

    16t^2 + 80t + 4 = 100

    Subtract 100 from both sides:

    16t^2 + 80t - 96 = 0

    Divide through by 16:

    t^2 + 5t - 6 = 0

    Factor:

    (t + 6)(t - 1) = 0

    Using the zero-factor property, we find the solution are:

    t = -6, 1

    So, the values of t which make the given expression equal to 100 are t = -6 and t = 1. :)
     
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  4. Mr.Lame

    Mr.Lame Veteran

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    Oh gawd, I made a terrible mistake LOL it's -16t^2

    I got the right answer now. Sorry mark T.T
     
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  5. MarkFL

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    You know, I should have realized that, because then it's a kinematic equation, representing the height of a projectile in feet whose initial upward velocity is 80 ft/s and whose initial height is 4 ft. :)
     
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  6. Mr.Lame

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    Yeah the answer is in ft too hahaha.I need to pay more attention to detail.

    Are you going to be on most of the day? I got a quiz tomorrow so, I may lean on you :) .
     
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  7. MarkFL

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    I'll be on for the next 4.5 hours or so, then off for 4, then I'll be back for the night. So, go ahead and post 'em up if you got 'em...:)
     
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  8. Mr.Lame

    Mr.Lame Veteran

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    Write the exponential expression in simplest form:
    (x^-2y)^2(xy)^-2

    so

    (x^4y^2)(x^-2y^-2)

    Then after that I'm clueless at how to get the answer, 1/x^6
     
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  9. MarkFL

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    This is how I would simplify:

    lame005.png
     
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  10. Mr.Lame

    Mr.Lame Veteran

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    OH Woah, I can't believe I didn't figure that out. So when they're in brackets like that we have to times the exponents.
     
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  11. MarkFL

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    Yes, there are two properties of exponents I used there:

    lame006.png
     
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  12. Mr.Lame

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    sweeeeeeet!!! Just helped me do a even harder equation :D Got the answer right first try !
     
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  13. Mr.Lame

    Mr.Lame Veteran

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    @MarkFL I have 0 idea how to do this

    Perform the indicated operation and wire the answer in scientific notation.
    (4.0x10^-9)(8.4x10^5) / (3.0x10^6)(1.4x10^18)

    So following what we just did, does that mean we times the numerators together, then the denominators, and finish off by dividing the numbers and subtracting the 10 powers?
     
  14. Mr.Lame

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    write*
     
  15. MarkFL

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    lame007.png
     
  16. Mr.Lame

    Mr.Lame Veteran

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  17. MarkFL

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    I had a typo, and needed to re-upload the image...can you see it now?
     
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  18. Mr.Lame

    Mr.Lame Veteran

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  19. Mr.Lame

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    Yup!! also I messed up it's ^-6
     
  20. Mr.Lame

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    ha.. ha.. ha.....
     

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