6. f(x) = 0.25x2 - 1 7. y = -x2+8 8. y = 7x2 + 2 9. y = 1.5x2 - 6x + 3 10. f(x) = 0.5x2 + 3x - 1 11. y = 3x2 - 5x + 1 12. f(x) = -3x2 - 6x - 4 13. A quadratic function is decreasing to the left of x = 3 and increasing to the right of x = 3. Will the vertex be the highest or lowest point on the graph of the parabola? Explain. 14. The graph of which function has the same axis of symmetry as the graph of y = 2x2 - 8x + 3? Explain your reasoning. A. y = -4x2 + 16x - 5 B. y = 2x2 + 8x +7 C. y = 3x2 - 6x + 7 D. y = -6x2 + 10x - 1 In Exercises 15-18, find the minimum or maximum value of the function. Describe the domain and range of the function, and where the function is increasing and decreasing. 3x2+ 12 16. y = -x - 6x 15