Can someone help me pls , thanks <3

What is the y intercept of f(x)=(1/2)^x?

Simplify the given expression leaving the answer in improper fraction form. 2/3+5/6

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