Please how can I convert y=-0.57x+8 into point slope form without being given 2 points

Explain how you do each step what term makes it inconsistent y=2x - 4 ?

If you could answer these your a life saver

The population of a small rural town in the year 2006 was 2,459. the population can be modeled by the function below, where f(x residents and t is the number of years elapsed since 2006. f(t) = 2,459(0.92)