Cogito
Integrated Math 2 · Chapter 1 · Lesson 2
Vertex Form and Transformations
Reading the vertex straight off the equation.
12 problems · about 21 minutes · F-BF.B.3, F-IF.C.8
Figure — use these to answer the problems
Warm Up
Straightforward practice. Get the method working first.
5 problemsy = (x − 6)² + 1. What is the vertex x-coordinate?
AnswerWhy does y = (x − 3)² have its vertex at x = 3?
- The bracket is zero there, which is its smallest possible value.
- It is an arbitrary rule about signs.
y = (x − 5)² + 2. Vertex x-coordinate?
Answery = (x + 4)² − 1. Vertex x-coordinate?
Answery = (x − 2)² + 7. What is the minimum value?
Answer
Build It Up
The same ideas with more to keep track of.
3 problemsTo complete the square on x² − 8x, what is added?
AnswerTo complete the square on x² + 10x, what is added?
Answery = −(x − 1)² + 9. What is the maximum value?
Answer
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
4 problemsPut the completing-the-square steps in order.
Write 1 to 4 in the boxes to put these in order.
- Halve the coefficient of x.
- Square that result.
- Add and subtract it inside the expression.
- Write the perfect square and collect the constants.
y = (x − 7)² − 3. Vertex y-coordinate?
AnswerThe Vertex
y = (x − 3)² − 4. What is the x-coordinate of the vertex?
AnswerThe Minimum
Same equation. What is the minimum value of y?
Answer