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anonymous

  • one year ago

FAN AND MEDAL! How do you solve -x^2+5x+6=0 ?

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  1. anonymous
    • one year ago
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    @warpedkitten @Empty @enchanted_bubbles @RedNeckOutLaw @Teddyiswatshecallsme @yomamabf @uybuyvf @ikram002p @imqwerty @OregonDuck @phi @abb0t @sammixboo @DullJackel09 @futureboy1 @GeniousCreation @Hero @jagr2713 @KAKES1967 @Loser66 @zmudz

  2. anonymous
    • one year ago
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    plz help

  3. zmudz
    • one year ago
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    quadratic formula should do the trick, or you could factor into \(-(x-6)(x+1)\) and solve for x that way

  4. anonymous
    • one year ago
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    @zmudz i did this but its wrong -x^2+5x+6=0 (-x^2-x)+(6x+6)=0 -x(x+1)+6(x+1)=0 (-x+6)(x+1)=0 -x+6=0 -x=-6 x=6 x+1=0 x=-1

  5. zmudz
    • one year ago
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    Ah, double check your math for when you solved x=-1

  6. anonymous
    • one year ago
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    no they are both wrong i used a graphing calculator and the zeroes are x=0 and x=-1.2

  7. anonymous
    • one year ago
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    it wants me to solve this system algebraically

  8. anonymous
    • one year ago
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    Lol your answers x=6 and x=1 are both correct.

  9. anonymous
    • one year ago
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    @phi i don't know what i did wrong in solving this

  10. anonymous
    • one year ago
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    If they want you to solve it algebraically, then why did you use a graphing calculator? :D

  11. phi
    • one year ago
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    I would first multiply both sides and all terms by -1 (because I don't like -x^2) what do you get ?

  12. anonymous
    • one year ago
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    because the second part is for me to graph it to prove my answers

  13. anonymous
    • one year ago
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    x^2-5x-6=0 @phi

  14. phi
    • one year ago
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    now try factoring it

  15. anonymous
    • one year ago
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    How I wish we were allowed to use a graphing calculator when we graph something. Do you know how to plot points like this? |dw:1439243109664:dw|

  16. phi
    • one year ago
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    but it looks like you did it correctly up top x= 6 and x=-1

  17. anonymous
    • one year ago
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    (x^2-2x)-(3x-6)=0 x(x-2)-3(x-2)=0 (x-3)(x-2)=0 x=3 and x=2

  18. anonymous
    • one year ago
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    wait i messed up on the sign there

  19. anonymous
    • one year ago
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    ok I'm confused @phi

  20. anonymous
    • one year ago
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    This is if you graph it

  21. phi
    • one year ago
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    (x^2 -6x) + (x-6) = 0

  22. phi
    • one year ago
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    ok, so \[ x^2 = 5x+6 \\ x^2 -5x-6=0\\ (x-6)(x+1)= 0 \\ x= 6 ; x= -1 \] y= 5x+6 so at x= -1, y= 1 at x= 6 , y= 36 here is the graph with the first solution showing

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  23. phi
    • one year ago
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    the solution is where the two curves cross (intersect) it is true when we are given a single curve (or line), we are often interested in where it crosses the x-axis (the x value is called the zero) but not in this case.

  24. anonymous
    • one year ago
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    and thats all?

  25. phi
    • one year ago
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    solving two equations is the same as asking "what point lies on both curves"

  26. phi
    • one year ago
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    there are two solutions -1,1 and (6,36)

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  27. anonymous
    • one year ago
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    ok thank you!

  28. phi
    • one year ago
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    you had the right idea except for the final step... once you found x= -1 or x=6 you find the y value (using either equation) and the (x,y) pairs are where the two curves intersect. i.e. are the "solutions"

  29. anonymous
    • one year ago
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    oh ok thank you i have to go :)

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