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Cogito

Algebra 1 · Chapter 8 · Lesson 4

Practice Worksheet

The Vertex and Axis of Symmetry

The turning point, and the mirror through it.

11 problems · about 23 minutes · F-IF.C.8, F-IF.B.4

NameDate

Figure — use these to answer the problems

Change b and watch the whole parabola slide sideways.

y = 1x² − 4x + 3

a1

b-4

c3

Figure 1

Warm Up

Straightforward practice. Get the method working first.

4 problems

y = x² − 10x + 2. Axis of symmetry, as an x value?
Answer
y = x² − 4x + 1. Axis of symmetry, as an x value?
Answer
y = x² − 4x + 1. What is the y of the vertex?
Answer
y = x² + 6x. Axis of symmetry, as an x value?
Answer

Build It Up

The same ideas with more to keep track of.

3 problems

Roots at 2 and 8. Where is the axis of symmetry?
Answer
a = 3. Is the vertex a minimum? 1 for yes, 0 for no.
Answer
y = x². Where is the vertex, as an x value?
Answer

Stretch Yourself

Mixed problems. Work out what kind of question it is before you start.

4 problems

Roots at −4 and 6. Where is the axis of symmetry?
Answer
9
Select every true statement about the vertex.
- It lies on the axis of symmetry.
- It is always a minimum.
- Its x is −b / 2a.
- It always sits on the x-axis.
- Tick every box that applies.
The Axis
y = x² − 8x + 1. What is the axis of symmetry, as an x value?
Answer
Max or Min
y = −x² + 4x. Is the vertex a maximum? 1 for yes, 0 for no.
Answer