This will clear up the last questions i asked

Aheated piece of metal cools according to the function c(x) = (.5)x ? 7, where x is measured in hours. a device is added that aids in cooling according to the function h(x) = ? x ? 2. what will be the temperature of the metal after two hours?

Add the two expressions 3.8b - 7 and 2.9b + 9 enter your answer in simplified form

What percent of 18 is 24? and plz explain thx.