Ireally need some . i need the slope intercept form y= mx + b form of the graph

sheleah and her family are planning a trip from los angeles, california to melbourne, australia. while booking her family's plane tickets, she notices on the itinerary that the airline is offering a sixteen hour straight flight from los angeles to melbourne on a boeing 747-8 intercontinental jet. in an effort to learn more about the capabilities of the jet, sheleah does a little research and stumbles upon the following graph and facts about the jet's gasoline consumption.

the boeing 747-8 intercontinental jet can carry approximately 422,000 gallons of gasoline, making it possible for the jet to travel 14,430 kilometers before needing to refuel.
use a linear model to predict the amount of gasoline that is present on the jet after it has been in flight for 18 hours without stopping to refuel. in two or more complete sentences, explain your answer.