I having trouble on this question

Aprojectile is thrown upward so that its distance above the ground after t seconds is given by the function h(t) = -16t2 + 704t. after how many seconds does the projectile take to reach its maximum height?

Let f(x) = 5/x and g(x)=2x2+5x. what two numbers are not in the domain of f o g

Jimmy can run 3.5 miles in 20 minutes. how far can ne run in one hour and ten minutes?