Rewrite this fraction as a decimal 15/4

Which problem could be  solved  by evaluating the expression  7×(−3)7×-3?

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.

Solve each quadratic equation by factoring and using the zero product property. n^2 - 49 = 0