What is the equation of the line that passes through the point (1,5) and has a slope of -1

Igor stravinsky tires sells approximately 3,760,000 car tires and 1,200,000 truck tires each year. about 47,000,000 care tires and 26,000,00 truck tires are sold each year in the united states. what is stravinsky's market share in each of these two markets (cars and trucks)?

1yd 1 ft = 1 1/12 1 1/3 1 1/2 1 1/6

Can you me find the slope! (30 points)