How does changing the value of m affect the graph of an equation in the form y=mx b?

Do you mind if you guys me with this question i’m on number 8

The price of a car has been reduced from $19,000 to $11,590. what is the percentage decrease of the price of the car?

The weight of a radioactive isotope was 96 grams at the start of an experiment. after one hour, the weight of the isotope was half of its initial weight. after two hours, the weight of the isotope was half of its weight the previous hour. if this pattern continues, which of the following graphs represents the weight of the radioactive isotope over time? a. graph w b. graph x c. graph y d. graph z