A model rocket is launched from the roof of a building. It's flight path through the air is modeled by h=-5tē+23t+10, where h is the height of the rocket above ground in meters and t is the time after the launch in seconds.

A) when does the rocket hit the ground?

I got this far H= -1(5tē-23t-10) -23-50

H= -1(t-25)(t+2) -25+2

The teacher answer has this..........

H= -1(5tē-23t-10)

H= -(t-5)(5t+2)

t-5= 0 5t+2=0

t=5 t=-2/5

Where does 5t come from?

I don't get the whole H= -5tē+23t+10 equation what does -5 stand for? 23t? 10?

Teacher just taught me the equation and I follow it but, I kinda dont get the whole thing.