1. REVIEW y = ax2 + bx + c is a parabola.  If a > 0, the parabola is oriented upward and the vertex is the minimum point of the function.  If a < 0, the parabola is oriented downward and the vertex is the maximum point of the function.  In either case the vertex of the parabola is located halfway between the roots (the zeros or x-intercepts.)  The x-coordinate of the vertex can be found by substituting the x-value of the vertex into the equation of the function that yields the y-value of the vertex.  The quadratic function may be given or it may need to be created based on the given information of the situation.

2. The coordinates of the vertex are (2, -13) and the minimum value of the function is –13.

3. Example 2 With 100 feet of fence, what are the dimensions of the corral of largest area that a farmer can create if his barn will provide one side of the corral? Let x = the width of the corral and then 100 - 2x is the length. The function which represents the area is y = (100 - 2x)x = -2x 2 + 100x The corral of maximum area has width x = 25 feet, length 50 feet, and area 1250 ft 2 W.S. Problems: 1, 2, 5,