Question 198830
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I already answered this question -- probably for you (and I say that because you are off on the same wrong tangent as before).

*[tex \LARGE \ \ \ \ \ \ \ \ \ \ f(x) = ax^2 + bx + c]

is the standard form of the quadratic function.

*[tex \LARGE \ \ \ \ \ \ \ \ \ \ ax^2 + bx + c = 0]

is the general form of the quadratic equation.  Two different things that you combined into one thing for some unknown reason.  Neither of them, nor the inappropriate combination that you provided, are of any value for finding the solution to the coin problem stated.  You are trying to saw a board in two using a teaspoon.

Go back and look at question 198744.  Paste the following link into your browser:

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