Me with this problems before my head explodes

What’s the domain of this function? fastttt

Jacob signs up to work for 2 1/2 hours at the school carnival. if each work shift is 3/4 hour, how many shifts will jacob work? (i just want to double check : |, for anybody that responds! : )

Maria walks a round trip of 0.75 mile to school every day.how many miles will she walk in 4.5 days