Points to be plotted on the graph → Vertex → (1, -9),
Zeros → (-2, 0), (2, 0)
y-intercept → (0, -8)
Other points → (1, -9), (-1, -5)
Graphing of a quadratic equation:
- To graph of a quadratic equation follow the following steps,
1). Find the x and y-intercepts.
2). Find the vertex of the parabola.
3). Find the points lying on the parabola.
4). Join the points.
Given in the question,
- Equation representing the graph → y = x² - 2x - 8
y = x² - 2x - 8
y = x² - 2(1)x + 1² - 1 - 8
y = (x - 1)² - 9
Therefore, vertex of the equation → (1, -9)
Substitute y = 0 for x-intercepts,
0 = (x - 1)² - 9
(x - 1)² = 9
x - 1 = ±3
x = -2, 2
Therefore, x-intercepts will be (-2, 0) and (2, 0).
For y-intercept, substitute x = 0,
y = 0² - 2(0) - 8
y = -8
Therefore, y-intercept will be (0, -8).
Table for the points on the parabola,
x y
3 -5
-1 -5
Now plot all these points on the graph and join them.
Therefore, graph of the quadratic equation will be as attached.
Learn more about the graphing a quadratic equation here,
https://brainly.com/question/20934835?referrer=searchResults
