The Extreme Value Theorem states that continuous functions on closed intervals have minimum and maximum values. An extremum is either a minimum or maximum value. A minimum occurs when the function value is less than or equal to all other values in the interval. A maximum occurs when the function value is greater than or equal to all other values in the interval. To find the absolute extrema, take the derivative and set it equal to 0 to find critical points, then substitute these back into the original function to determine the minimum and maximum values.