The moon is about 240,000 miles from earth what is the distance written as a whole number multiplied by a power of 10

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.

Ammonia molecules have three hydrogen atoms and one nitrogen atom.how many of each atom arein five molecules of ammonia

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?