algebra help

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(-2,2) (4,20)
Find the value of x when y is 9.

  • algebra help -

    I will assume you want
    (-2,2) , (x,9) , and (4,20) to lie on the same straight line?

    if so,
    method I : find the equation of the line using the two known points, then sub in y=9

    Method II : just set up a ratio ...
    (x+2)/(9-2) = (4+2)/(20-2)
    (x+2)/7 = 1/3
    3x + 6 = 7
    x = 1/3

  • algebra help -

    how do you graph the function for p(x)=2x^2=12,500 where x is the number of items sold x(underscore)>3

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