The problem asks us to graph the quadratic equation $y = -x^2 + 10x - 9$ by making a table of values. We need to find the vertex and the roots of the quadratic to determine the height and distance of the water balloon launched from a toy catapult.
2025/5/14
1. Problem Description
The problem asks us to graph the quadratic equation by making a table of values. We need to find the vertex and the roots of the quadratic to determine the height and distance of the water balloon launched from a toy catapult.
2. Solution Steps
First, we make a table of values for x and y.
To find the vertex of the parabola, we can use the formula for the x-coordinate of the vertex:
, where and in the equation .
Now, we find the y-coordinate of the vertex by plugging into the equation:
So, the vertex is at .
To find the roots (where the balloon lands), we set and solve for :
We can factor this quadratic equation:
So, the roots are and .
Now, let's make a table of values around the vertex and roots:
| x | y = -x^2 + 10x - 9 |
|---|---------------------|
| 0 | -0^2 + 10(0) - 9 = -9 |
| 1 | -1^2 + 10(1) - 9 = 0 |
| 2 | -2^2 + 10(2) - 9 = -4 + 20 - 9 = 7 |
| 3 | -3^2 + 10(3) - 9 = -9 + 30 - 9 = 12 |
| 4 | -4^2 + 10(4) - 9 = -16 + 40 - 9 = 15 |
| 5 | -5^2 + 10(5) - 9 = -25 + 50 - 9 = 16 |
| 6 | -6^2 + 10(6) - 9 = -36 + 60 - 9 = 15 |
| 7 | -7^2 + 10(7) - 9 = -49 + 70 - 9 = 12 |
| 8 | -8^2 + 10(8) - 9 = -64 + 80 - 9 = 7 |
| 9 | -9^2 + 10(9) - 9 = -81 + 90 - 9 = 0 |
| 10| -10^2 + 10(10) - 9 = -100 + 100 - 9 = -9 |
The graph is a parabola opening downwards. The vertex is the highest point, so the maximum height is 16 yards. Since the launch is from the one-yard line, the water balloon lands at , so it traveled yards.
3. Final Answer
The water balloon reached a maximum height of 16 yards. It landed 8 yards from where it was launched (at the 9-yard line). The vertex of the parabola represents the maximum height, and the roots (x-intercepts) represent where the balloon lands. Since the launch point is the 1-yard line, we subtract 1 from the root that gives the landing position, which is