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kirk.freedman Group Title

Use the quadratic formula to solve the equation. x^2 – 7x – 6 = 0 Show work please.

  • one year ago
  • one year ago

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  1. winterfez Group Title
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    x^2-7x-6=0?

    • one year ago
  2. lilg132 Group Title
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    \[x = \frac{ -b \pm \sqrt{b ^{2} -4ac} }{ 2a}\]

    • one year ago
  3. kirk.freedman Group Title
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    yes it is an exponent

    • one year ago
  4. lilg132 Group Title
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    x2 = a -7x = b -6 = c x2 = 1 -7x = -7 -6 = -6

    • one year ago
  5. tcarroll010 Group Title
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    \[x = \frac{ -b \pm \sqrt{b ^{2}-4ac} }{ 2a }\]where a=1, b=-7, and c =-6 This is because your equation is in the standard form of ax^2 + bx + c = 0. So, now, just make the substitutions.

    • one year ago
  6. kirk.freedman Group Title
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    Hmm, ok thanks, let me work this out and I will reply to what I got to check if it is right.

    • one year ago
  7. tcarroll010 Group Title
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    Hint: after you make your substitutions, pay special attention to the expression within the radical (the square root sign). You will see that the numbet in the radical is positive, so you will have two real solutions. But your final solution will have a radical in it.

    • one year ago
  8. winterfez Group Title
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    |dw:1354234621716:dw|

    • one year ago
  9. tcarroll010 Group Title
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    Are you able to identify the variables a, b, and c and make the substitutions?

    • one year ago
  10. kirk.freedman Group Title
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    Yes, I got to the step that winterfezz last showed, but I don't know what to do now

    • one year ago
  11. tcarroll010 Group Title
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    Start with the expression within the radical. Start with (-7)^2. That is the same as 7^2.

    • one year ago
  12. winterfez Group Title
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    |dw:1354234898685:dw| you get 2 answers

    • one year ago
  13. tcarroll010 Group Title
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    And when you have a negative number times a positive number, the product will be negative.

    • one year ago
  14. tcarroll010 Group Title
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    So, can you determine (-7)^2 ?

    • one year ago
  15. tcarroll010 Group Title
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    (-7)^2 is the same as (-7)(-7) and that is the same as (7)(7)

    • one year ago
  16. kirk.freedman Group Title
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    Yes, tcarroll, I know all that basic math stuff xD I am at the part where I have |dw:1354235055422:dw|

    • one year ago
  17. tcarroll010 Group Title
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    That's good!. Because that is your final answer! Well done!

    • one year ago
  18. kirk.freedman Group Title
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    So I do not simplify it further?

    • one year ago
  19. tcarroll010 Group Title
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    That's as far as you can take it.

    • one year ago
  20. tcarroll010 Group Title
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    It is customary to leave it with the +- sign

    • one year ago
  21. kirk.freedman Group Title
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    Ok, so no decimal needed, I just leave it as this?

    • one year ago
  22. tcarroll010 Group Title
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    That's good just like that.

    • one year ago
  23. kirk.freedman Group Title
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    Thank both of you very much!:)

    • one year ago
  24. tcarroll010 Group Title
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    \[\frac{ 7\pm \sqrt{73} }{ 2 }\]Like that

    • one year ago
  25. tcarroll010 Group Title
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    You're very welcome!

    • one year ago
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