Simplify the expression (9n+ 4)-(-1/2n-7)

Anabel uses 10 gallons of gas to drive 220 miles on the highway. if she travels at the same rate, how many miles can she drive on 7 gallons of gas

Twenty-five percent of the customers entering a grocery store between 5 p. m. and 7 p. m. use an express checkout. consider five randomly selected customers, and let x denote the number among the five who use the express checkout.

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.