I really need help. Can you please show your work too.

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

Aball is thrown from a height of 139 feet with an initial downward velocity of 15 ft/s. the ball's height h (in feet) after t seconds is given by the following. h=139-15t-16t^2 how long after the ball is thrown does it hit the ground? round your answer(s) to the nearest hundredth. (if there is more than one answer, use the "or" button.) t =

Xy x xy if a and b are positive integers such that a*b=9 and b*a=72 what is the value of a/b