The quadratic function is .

For this function a = , so the graph opens down and the function has a maximum value.

The maximum value of the function is the y-coordinate of the vertex.

The - coordinate of the vertex is .

        (Substitute the values a = and b = )

               (simplify) \ \

\ \

The y-coordinate of the vertex by evaluating the function for = .

\ \

                         (Original function)

         ( = )

. \ \

The maximum value of the function is  .

The function has maximum value.

The maximum value of the function is . \ \