Simplify: 5 - 3 + 7 - (-9)

At which value in the domain does f(x) =0?

Hi my sisters and brothers can tell me the answer because i don’t understand the 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?