Which of these statements is true for f(x)=(9/10)^x

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

Janie has $3. she earns $1.20 for each chore she does and can do fractions of chores. she wants to earn enough money to buy a cd for $13.50. write an inequality to determine the number of chores, c, janie could do to have enough money to buy the cd.

What is the range? can’t seem to find it out