Can someone help me answer this question especially c

Igebra 2A Unit 2 Process Questions 1. The approximate path of a projectile launched from 70 m above the ground is given by f(x) =-5x2 + 25x + 70, where f(x) represents the height x seconds after it is released into the air. Use this information to answer the questions below. Show your work. a. What is the factored form of the equation? b. How long will it take the projectile to reach the ground? c. After how many seconds will the projectile return to its original launch height? MAY