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anonymous

  • 5 years ago

5x²=-7x-2

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  1. anonymous
    • 5 years ago
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    rearrange 5x^ 2 +7x + 2 = 0 Factorising: (5x +2)(x+1)=0 x = -2/5 , -1

  2. angela210793
    • 5 years ago
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    5x²+7x+2=0 D=b^2-4ac Same way as the other 1

  3. anonymous
    • 5 years ago
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    oh! I assumed u wanted to solve it!

  4. angela210793
    • 5 years ago
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    if ur factorising it is right u have solved it :)

  5. anonymous
    • 5 years ago
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    yeah i know but did tina want to know the value of the determinant?

  6. angela210793
    • 5 years ago
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    i have explained her earlier wht should she put instead of a,b and c....she can find the value herself i guess :)

  7. angela210793
    • 5 years ago
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    D=49-4*5*2=9 X1=(-b+sqrD)/2a=(-7+3)/2*5=-4/10=-2/5 X2=(-b-sqrD)/2a=(-7-3)/2*5=-10/10=-1 :)

  8. amistre64
    • 5 years ago
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    Put the x's to one side 5x² +7x = -2 ; divide out the 5 x^2 + (7/5)x = (-2/5) ; complete the square x^2 +(7/5)x+ (7/10)^2 = (-2/5) + (7/10)^2 ; clean it up (x+7/10)^2 = 9/100 ; sqrt the sides x+7/10 = +- 3/10 ; -7/10 x = -7/10 +- 3/10 x = -10/10 , and x = -4/10

  9. amistre64
    • 5 years ago
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    x = -1, and x = -2/5

  10. angela210793
    • 5 years ago
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    hmmmm.....i didn't know this way of solving this....(my way is shorter and better anyway :P )

  11. amistre64
    • 5 years ago
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    completing the square is how we generalize going from: ax^2 +bx +c <-> x = (-b +- sqrt(b^2-4ac))/2a

  12. anonymous
    • 5 years ago
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    there u go! solving by factorising, the general formula and completing the square!!

  13. amistre64
    • 5 years ago
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    they first learn to "complete the square" so that you understand how the quad fromula is derived

  14. amistre64
    • 5 years ago
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    otherwise, its simplying teaching to "FOIL" and they learn a memorization technique and remain ignorant about how or why it works :)

  15. anonymous
    • 5 years ago
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    right

  16. angela210793
    • 5 years ago
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    ''Thnx a loot" X(

  17. amistre64
    • 5 years ago
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    How do I get to SanJose from here? I dunno, but Ill know when were there lol

  18. angela210793
    • 5 years ago
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    U mean u'll know when u'll** be there? O.o

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