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anonymous

  • one year ago

Help please Find the equation of the axis of symmetry and the coordinates of the vertex of the graph of the function y = –2x^2 +6x – 1. A) x = 3; vertex: (3, 35) B) x = –1.5; vertex: (–1.5, – 14.5) C) x = –1.5; vertex: (–1.5, –5.5) D) x = 1.5; vertex: (1.5, 3.5)

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  1. popitree
    • one year ago
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    from the equation, after simplifying u will get \[(x-\frac{ 3 }{ 2 })^{2} = -\frac{ y }{ 2 }+\frac{ 7 }{ 4 }\]

  2. popitree
    • one year ago
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    now can u solve

  3. Nnesha
    • one year ago
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    this question is same just like we did on the previous thred \[\huge\rm \frac{ -b }{ 2a }\] use this formula to find x-coordinate of the vertex

  4. anonymous
    • one year ago
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    IN the general quadratic\[y=ax^2 + bx + c\]the axis of symmetry is the vertical lineline\[x=-\frac{ b }{ 2a }\]Yhis also gives the x-coordinate of the vertex. Plug this value of x back into the function to get the y-coordinate of the vertex.

  5. Nnesha
    • one year ago
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    and then replace x by its value into the equation to find y-coordinate axis of symmetry = x coordinate of the vertex

  6. anonymous
    • one year ago
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    can we go over this step by step.. still confused So I replace b with -2 and a with 6? @Nnesha

  7. Nnesha
    • one year ago
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    no \[\huge\rm Ax^2+Bx+C=0\] B is middle term A is leading coefficient

  8. anonymous
    • one year ago
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    Oh actually the opposite I mean.. -2 -> a and 6 -> b

  9. Nnesha
    • one year ago
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    yes!!

  10. Nnesha
    • one year ago
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    substitute b and a by their values into the formula

  11. anonymous
    • one year ago
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    -(6)/2(-2)

  12. Nnesha
    • one year ago
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    yes!

  13. anonymous
    • one year ago
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    so now we divide by -2?

  14. Nnesha
    • one year ago
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    there is 2(-2) you can multiply them first or reduce the fraction

  15. anonymous
    • one year ago
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    -(6)/-4

  16. Nnesha
    • one year ago
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    yes right :=)

  17. Nnesha
    • one year ago
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    can you reduce the fraction -6/-4 = ?

  18. anonymous
    • one year ago
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    so now we simplify

  19. anonymous
    • one year ago
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    yes divide by 2 or -2

  20. Nnesha
    • one year ago
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    okay so -6/-4 = ?

  21. anonymous
    • one year ago
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    3/2

  22. anonymous
    • one year ago
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    and then 3/2 = 1.5 right?

  23. Nnesha
    • one year ago
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    yes right

  24. Nnesha
    • one year ago
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    now find y-coordinate of the vertex

  25. anonymous
    • one year ago
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    y = -2(1.5)^2 + 6(1.5) - 1?

  26. Nnesha
    • one year ago
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    yes

  27. anonymous
    • one year ago
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    = 3.5

  28. anonymous
    • one year ago
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    the answer is D

  29. anonymous
    • one year ago
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    D) x = 1.5; vertex: (1.5, 3.5)

  30. Nnesha
    • one year ago
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    yes right!

  31. anonymous
    • one year ago
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    thanks

  32. Nnesha
    • one year ago
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    my pleasure

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