Help with procedures please

*A model for the height of a toy rocket shot from a platform is y=-16x^2+145x+7, where x is the time in seconds and y is the height in feet.

a)Graph the function

b)Find the zeros of the function( i get a weird root)

c)What do the zeros represent? Are tehy realistic? (answered)

d)About how high does the rocket fly before hitting the ground? explain???

*what are multiple zeroes? Explain how you can tell if a function has multiple zeroes.

*A polynomial equation with rational coefficeints has root of 7 and negative root of 3. Explain how to find two additional roots and name them.

I know that hte additional roots will be negative root of 7 and positive root of 3... what do you mean by name them?

Thanks for the help (Hi)