Answer:
The maximum value is 5
Explanation:
Since this is an upside-down parabola, the maximum value occurs at the vertex. Using -b/2a, we can find the x-value of the vertex and use that x value to plug back into the original function to find the maximum value.
x = -b/2a = -(-12)/(2(-6)) = 12/-12 = -1
f(-1) = -6(-1)^2-12(-1)-1 = 5