Simple khan academy math help asap

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?

8000 + 8800 + 8000 + 8 million + 80 trillion + another a katrillion equals

Two variables, x and y, vary inversely, and x=12 when y=4. what is the value of y when x=3?