I need help with these two! Pick the correct description :)

Will mark brainliest

The swimming pool is open when the high temperature is higher than 20∘c. lainey tried to swim on monday and thursday (which was 3 days later). the pool was open on monday, but it was closed on thursday. the high temperature was 30∘c on monday, but decreased at a constant rate in the next 3 days. write an inequality to determine the rate of temperature decrease in degrees celsius per day, d, from monday to thursday.

Simplify the expression below -3(10x+4y)+6(6x-2y)

At a cost of 200, your club bought 175 frisbees to sell at the pep rally. you plan on selling them for $5 each. what is the domain of the function?