Question

As Isla prepares to set off fireworks, she wants to ensure the spectators are a safe distance away. When shot in the air, one firework will follow the path h(x)=−x^2+15x , where h(x) is the height of the firework, and x is the horizontal distance it travels in feet. To determine how far the firework will travel before it reaches the ground, Isla sets the height equal to zero, and solves the following quadratic equation: 0=−x^2+15x . How far will the firework travel before it reaches the ground?(1 point)
Responses

15 feet
15 feet

−15 feet
negative 15 feet

7.5 feet
7.5 feet

30 feet
30 feet

Answer 1

To find out how far the firework will travel before it reaches the ground, we need to solve the quadratic equation:

\[ 0 = -x^2 + 15x. \]

First, we can rearrange this equation:

\[ -x^2 + 15x = 0. \]

Next, we can factor out an \( x \):

\[ x(-x + 15) = 0. \]

Setting each factor equal to zero gives us:

1. \( x = 0 \)
2. \( -x + 15 = 0 \) which simplifies to \( x = 15 \).

The firework will reach the ground when \( x = 15 \) feet (after being shot into the air).

Therefore, the firework will travel **15 feet** before it reaches the ground.

**Answer:** 15 feet