***ALGEBRA***
Write a two step equation that has a solution of x=7.5

An astronaut drops a rock into a crater on the moon. the distance, d(t), in meters, the rock travels after t seconds can be modeled by the function d(t)0.82. what is the average speed, in meters per second, of the rock between 5 and 10 seconds after it was dropped?

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.

What numbers are included in the set of integers? what numbers are not included?