Before we can determine the absolute extrema of the function, let's graph the given function first. f(x) = x² - 6x.
For the interval [-1, 6], we can see that the maximum value would be at x = -1.
Let's replace x with -1 in the function above.
[tex]\begin{gathered} f(x)=x^2-6x \\ f(-1)=(-1)^2-6(-1) \\ f(-1)=1+6 \\ f(-1)=7 \end{gathered}[/tex]Therefore, the maximum between the interval [-1, 6] is at (-1, 7).
On the other hand, looking at the interval (3, 7] in the graph, the maximum is found at x = 7. To determine the maximum point, replace "x" with 7 in the function above.
[tex]\begin{gathered} f(7)=7^2-6(7) \\ f(7)=49-42 \\ f(7)=7 \end{gathered}[/tex]Therefore, the maximum at the interval (3, 7] is at point (7, 7).