To find how far the firework will travel before it reaches the ground, we need to solve the quadratic equation given by:
\[ 0 = -x^2 + 15x \]
We can rearrange this equation as follows:
\[ -x^2 + 15x = 0 \]
Factoring out \(x\):
\[ x(-x + 15) = 0 \]
Setting each factor to zero gives us the potential solutions:
- \( x = 0 \)
- \( -x + 15 = 0 \) → \( x = 15 \)
The solutions indicate that the firework reaches the ground at \(x = 0\) feet (the launch point) and \(x = 15\) feet (the point where it lands).
Thus, the firework will travel 15 feet before it reaches the ground.
The correct response is:
15 feet.