1.

The painting of an unknown artist was worth $85 in 1978. As the artist grew in popularity the value of this painting grows in value at the rate of 9% per year.

If I were to write an equation that represents the question above, would it be y=85(1.09)^x ? Or is it y=100(0.91)^x?

(equation to represent the valuey, in dollars, of the painting as a function of the number of years,x)

2.

Caffeine, found in pop, coffee, and tea, travels in your bloodstream after you consume it. After you drink a beverage that contains caffeine, 13% of the caffeine in your blood is removed every hour (Initially100% of the caffeine is present)

If I were to write an equation that represents the question above, would it be y=100(13/100)^x? Or is it y=100(87)^x?