Answer:
15 units
Step-by-step explanation:
Given the equation which models the path of a stone as:
[tex]H(x)=-5x^2+10x+15[/tex]
At the time when the stone was thrown
x=0
Therefore:
[tex]H(0)=-5(0)^2+10(0)+15\\H(0)=15[/tex]
The height of the stone at the time it is thrown is 15 units.