## Fundamentals of Physics Extended (10th Edition)

If you plug in a positive number for t on all the functions, you will get a positive value for X in functions 1 and 3, and a negative value for X in function 2. The rock is initially traveling in the positive direction, therefore function 2 is the only function that is directed opposite to the rock's initial direction. Example: let t=10 1)x=4(10)-3_________________x=37 2)x=-4($10^{2}$)+6(10)-3______x=-343 3)x=-4($10^{2}$)+6(10)-3______x=457