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C. x-intercepts and Zeros



 Key Lesson Marker

  Variables a and c


Interpreting \(f(x) = ax^2 + bx + c \),  \(a \ne 0\)
direction of opening up when \(a > 0\) and down when \(a < 0 \)
\(y\)-intercept corresponds to the \(c\)-value (let \(x = 0\), and determine the value of \(y\))

In Section B, you saw that changing \(a\), \(b\), and \(c\) in \(f(x) = ax^2 + bx + c, a \ne 0\) changed the shape, location, and/or orientation of the graph. However, you also saw what limited information is readily available from this form. Rewriting the function in different forms makes additional information more readily available.

In Section C, you will discover how the \(x\)-intercepts of the graph of a quadratic function can easily be determined when the function is expressed in factored form.