You might have to change the viewing window in order to see the graph.
Maximum Value: 23
Practice makes perfect
We want to find the minimum or maximum value of the given function.
y=-9x^2-12x+19
Because the leading coefficient is negative, we know we are looking for a maximum value. Now, let's draw the function on a graphing calculator. We begin by pushing the Y= button and typing the equation in the first row.
Having entered the equation in the calculator, we now push GRAPH to draw it.
For this function, we cannot see the maximum value in the standard viewing window. We can resize our window by pushing WINDOW, changing the settings, and once more pushing GRAPH. Note that the constant is 19, so this is the y-intercept. Recognizing this gives us an idea of how high our window should go.
Next, to find the maximum, push 2nd and TRACE. From this menu, choose maximum.
The calculator will prompt you to choose left and right bounds and to provide the calculator with a best guess of where the maximum might be.
Maximum and minimum values refer to a function's y-value. Therefore, the function's maximum y-value is 23.
