9. What do the x-intercepts of the graph represent in the context of the problem situation? 10. How does increasing the c-value from 0 to 6 translate the graph? Why? 11. How does increasing the c-value from 0 to -7 translate the graph? Why? 12. What happens to the parabola when the c-value is increased (c>0)? 13. What happens to the parabola when the c-value becomes negative (c < 0)? 14. How is the graph of y = x+1 similar to the graph of y = x-1? How are the graphs different?