Alain throws a stone off a bridge into a river below.
The stone's height (in meters above the water), xxx seconds after Alain threw it, is modeled by h(x)=-5x^2+10x+15
What is the height of the stone at the time it is thrown?

for this case we must apply distributive property to the following expression:

the distributive property states that:

then, when applying the property we have to multiply the -2 for each term within the parenthesis:

a is the best answer choice