This is an easy question but it’s kind of stumping me, please help!!

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)?

The radius of the earth is two times the radius of the moon. what fraction of the volume of the earth is the volume of the moon?

Can someone factor this fully? my friend and i have two different answers and i would like to know if either of them is right. you in advance. a^2 - b^2 + 25 + 10a