What's 9+10 use your head you should know this by now

After two years, how much has been paid into interest?

Solve the system of equations. y= 2x y= x^2 - 15

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.