Find the missing side. Round to the nearest tenth

Need same math paper but the back now i hope your able to read it cleary i need with hw

Graph the line with the given slope m and y-intercept b. m=-3,b=1

The bolo cavern outside of vandalia is 421 ft below sea level. a little more than75 miles away. mt owens is 7295 feet above sea level. what is the difference in elevation between the bolo cavern and mt owens?