ANSWER
-30.25
EXPLANATION
The maximum or minimum value of a parabola is the y-coordinate of the vertex. If the parabola is given in the standard form,
[tex]f(x)=ax^2+bx+c[/tex]Then the x-coordinate of the vertex is,
[tex]x_{vertex}=\frac{-b}{2a}[/tex]And the y-coordinate of the vertex is,
[tex]y_{vertex}=f(x_{vertex})[/tex]In this case, a = 1, and b = 5, so the x-coordinate of the vertex is,
[tex]x_{vertex}=\frac{-5}{2\cdot1}=-\frac{5}{2}[/tex]And the y-coordinate is,
[tex]y_{vertex}=\left(-\frac{5}{2}\right)^2+5\left(-\frac{5}{2}\right)-24=\frac{25}{4}-\frac{25}{2}-24=\frac{25-50-96}{4}=\frac{-121}{4}=-30.25[/tex]Hence, the minimum/maximum value of this parabola is -30.25.