# Introduction to Graphing Quadratic Equations

```Graphing Quadratic Equations – Day 2
Quick Review
Standard form of a quadratic equation:
Yesterday when we graphed quadratic equations we used the same x values in our tables because the
equations we graphed did not have any “b” values. If you were to graph y = x2 + 6x + 8 and used the
same x values as we did yesterday, what kind of shape would the graph make?
y = x2 + 6x + 8
x
y
2
1
0
-1
-2
Example 1
Graph y = x2 + 6x + 8.
In order to know what x values to use to graph, we are going to find the vertex of the parabola first so we
can choose x values for our table.
The formula for finding the vertex of a parabola is:
For y = x2 + 6x + 8 , a = _____, b = _____, c = _____
The vertex of y = x2 + 6x + 8 would be:
x
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y
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Graphing Quadratic Equations – Day 2 Homework
Name: _____________________
Example 2: Graph y = -x2 + 6x – 1 (remember to find the vertex first)
x
y
Now you graphed the equation, name the:
axis of symmetry:
x-intercepts:
Example 3: Graph y = 2x2 + 8x + 6
x
y
axis of symmetry:
x-intercepts:
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Graphing Quadratic Equations – Day 2 Homework
Name: _____________________
Example 3: Graph y = x2 – x – 2
x
y
axis of symmetry:
x-intercepts:
Example 4: Graph y = -x2 – 6x – 7
x
y
axis of symmetry:
x-intercepts:
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```