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Math Help - Quadratic function probelm

  1. #1
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    Quadratic function probelm

    Hi
    Need help on the following question:
    1) A straight line with gradient 2 passes through the vertex of the parabola y= x^2-5x+3. What is the equation to the line?

    P.S
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  2. #2
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    Hello Paymemoney
    Quote Originally Posted by Paymemoney View Post
    Hi
    Need help on the following question:
    1) A straight line with gradient 2 passes through the vertex of the parabola y= x^2-5x+3. What is the equation to the line?

    P.S
    I don't know what method you use for finding the vertex of a parabola, but you can complete the square:
    y= x^2-5x+3
    =\left(x-\frac52\right)^2 -\frac{25}{4}+3

    =(x-2.5)^2 -3.25

    So the vertex is at (2.5, -3.25). Now use
    y -y_1 = m(x-x_1)
    to find the equation of the line.

    Can you complete it now?

    Grandad
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  3. #3
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    Quote Originally Posted by Grandad View Post
    Hello PaymemoneyI don't know what method you use for finding the vertex of a parabola, but you can complete the square:
    y= x^2-5x+3
    =\left(x-\frac52\right)^2 -\frac{25}{4}+3

    =(x-2.5)^2 -3.25

    So the vertex is at (2.5, -3.25). Now use
    y -y_1 = m(x-x_1)
    to find the equation of the line.

    Can you complete it now?

    Grandad

    thank you i understand now.
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