For all functions of the form f of x is equal to A x squared plus b x plus c , which is true when b is equal to 0 ?

When b = 0, the function is f(x) = Ax² + c. Its vertex is at x = −b/(2A) = 0, and the y-intercept also occurs at x = 0, so the y-intercept is the vertex. The function may open downward, so it does not always have a minimum.

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