H(x) = -5x2 + 10x + 15
What is the height of the stone at the time it is thrown?

The height of the stone at the time it is thrown is 15.

Step-by-step explanation:

You have a quadratic function of the form h (x) = ax² + bx + c. In this case it is h (x) = -5x²+10x+15, where a =-5, b =10, c =15, x is the time and h (x) is the height of the stone after being thrown.

The moment the stone is thrown is instant zero. So if x = 0, h (0) is calculated:

h(0)= -5*0² +10*0 +15

h(0)= 0 + 0 + 15

h(0)= 15

The height of the stone at the time it is thrown is 15.

i think it is c, not positive though

step-by-step explanation: