Evaluate Quadratic Functions Question Given \( f(x)=-x^{2}+x+15 \), find \( f(-8) \) Examples Answer \( \begin{array}{l}\text { Attempt } 1 \text { out of a }\end{array} \) \( \begin{array}{l}\text { Submit Answer }\end{array} \)

To find \( f(-8) \), substitute -8 into the function: \( f(-8) = -(-8)^2 + (-8) + 15 = -64 - 8 + 15 = -57. \) Thus, \( f(-8) = -57 \). Quadratic functions like this one can be visualized as parabolas. The graph opens downward since the coefficient of \( x^2 \) is negative. The vertex, or the highest point of the parabola, will provide us with the maximum value—perfect for visualizing how changes in \( x \) affect \( f(x) \)! When evaluating quadratic functions, a common mistake is forgetting to square the \( x \) value before applying it into the function. Always double-check your arithmetic—especially signs! It’s easy to mix up the negative signs, especially when dealing with larger numbers. Stay sharp!