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kirk.freedman Group Title

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

  • 2 years ago
  • 2 years ago

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

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

    • 2 years ago
  3. kirk.freedman Group Title
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    yes it is an exponent

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

    • 2 years 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.

    • 2 years 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.

    • 2 years 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.

    • 2 years ago
  8. winterfez Group Title
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    |dw:1354234621716:dw|

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

    • 2 years 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

    • 2 years 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.

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

    • 2 years 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.

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

    • 2 years 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)

    • 2 years 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|

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

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

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

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

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

    • 2 years ago
  22. tcarroll010 Group Title
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    That's good just like that.

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

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

    • 2 years ago
  25. tcarroll010 Group Title
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    You're very welcome!

    • 2 years ago
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