Plz help me on 9&10 and plz explain work! Thank you

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

What is the difference between the equations of a vertical and a horizontal line?

According to the 2008 u.s. census, california had a population of approximately 4 × 10^7 people and florida had a population of approximately 2 × 10^7 people. which of the following is true? a. the population of california was approximately two times the population of florida. b. the population of florida was approximately twenty times the population of california. c. the population of florida was approximately two times the population of california. d. the population of california was approximately twenty times the population of florida.