The sum of two numbers is 19. The difference is 9. What are the two numbers?

Can someone pls ! pls answer all. no explanation needed..

According to modern science, earth is about 4.5 billion years old and written human history extends back about 10,000 years. suppose the entire history of earth is represented with a 10-meter-long timeline, with the birth of earth on one end and today at the other end.

Write an equation for the function that includes the points (2,100)and (3,100)