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kirk.freedman

  • 2 years ago

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

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  1. winterfez
    • 2 years ago
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    x^2-7x-6=0?

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

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

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

  5. tcarroll010
    • 2 years ago
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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.

  6. kirk.freedman
    • 2 years ago
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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.

  7. tcarroll010
    • 2 years ago
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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.

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

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

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

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

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

  13. tcarroll010
    • 2 years ago
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    And when you have a negative number times a positive number, the product will be negative.

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

  15. tcarroll010
    • 2 years ago
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    (-7)^2 is the same as (-7)(-7) and that is the same as (7)(7)

  16. kirk.freedman
    • 2 years ago
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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|

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

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

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

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

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

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

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

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

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

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