Arocket on a computer screen has a path modeled by the equation h=-t2+3t+10 where t is time in seconds and h is the height above a platform and is in computer units. find how long the rocket takes to reach the platform.
a - 2 seconds
b - 10 seconds
c - 12 seconds
d - 5 seconds

When the rocket reaches the platform, then h must be equal to 0

h=0

Calculating for t using the equation:

h=-t^2+3t+10

0 = -t^2+3t+10
reversing sides: 
t^2 -3t -10 = 0 

By completing the squares or factoring, we can get the roots: 

(t-5)(t+2) =0 
t=5 or t=-2 

Since time cannot be negative, therefore: 

t = 5 seconds 

Answer is D.

The time taken by the rocket to reach the platform is 5 seconds.

According to the question, the path model of the rocket on the computer screen is where, is time in seconds and is the height above the platform.

If the rockets reaches to the platform then, the height above the platoform for the rocket must be equals to zero.

So,

Hence, the time taken by the rocket to reach the platform is 5 seconds.

Learn more about quadratic equations here:

link

go on the tube you might find some information there