Can you answer my screenshot

Which of the following best describes the figure?

The value, v, of kalani’s stock investments over a time period, x, can be determined using the equation v=750(0.80)^-x. what is the rate of increase or decrease associated with this account? 20% decrease 20% increase 25% decrease 25% increase

If x varies directly as y, and x = 7.5 when y = 10, find x when y = 4