Math 2 (L1-2) A.SSE.3, F.IF.8 Assessment Title: Factored Form of a

Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
Learning Targets:
ο‚· Use factored form to identify key features of a quadratic function
Part I: Looking back at linear functions.
Consider the function: 𝑓(π‘₯) = 2π‘₯ – 6
1. Identify the y-intercept by substituting 0 for x:
( _______ , _______ )
2. Identify the x-intercept substituting 0 for 𝑓(π‘₯):
( _______ , _______ )
3. Using the intercepts, graph the function.
Calculating the x and y-intercepts of a function is a slick way to graph the function. We can use
this technique for other functions that are not linear, such as quadratic functions.
Part II: The Zero Product Rule
1. Determine 0 ο‚· 5 ο‚· 12 ο‚· 119 =____________
2. Determine (ο€­7) ο‚· (315) ο‚· (0) ο‚· (89) =____________
3. Determine (13)(21)(0) = ____________
4. What can you conclude from the example problems above?
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
5. If (π‘₯ βˆ’ 4)(π‘₯ + 8) = 0, find the value(s) for π‘₯. Show your work and explain how you got
your answers.
6. If we are given (π‘₯ βˆ’ 4)(π‘₯ + 8)(π‘₯ βˆ’ 2) and their product is 0, then one of the individual
factors MUST be 0.
Therefore, (π‘₯ βˆ’ 4)(π‘₯ + 8)(π‘₯ βˆ’ 2) = 0 when π‘₯ = 2, π‘₯ = _______, π‘Žπ‘›π‘‘ π‘₯ = ______.
7. Solve (π‘₯ βˆ’ 10)(π‘₯ + 6) = 0 π‘₯ = _______ π‘Žπ‘›π‘‘ π‘₯ = __________
8. Solve (2π‘₯ βˆ’ 8)(π‘₯ βˆ’ 12) = 0 π‘₯ = ______ π‘Žπ‘›π‘‘ π‘₯ = __________
9. Solve (3π‘₯ βˆ’ 2)(5 βˆ’ π‘₯) = 0
10. Solve (π‘₯ βˆ’ 𝐴)(π‘₯ βˆ’ 𝐡) = 0
π‘₯ = ______ π‘Žπ‘›π‘‘ π‘₯ = __________
π‘₯ = ______ π‘Žπ‘›π‘‘ π‘₯ = __________
In general, to determine when a product of linear factors is equal to 0, just set each individual
factor equal to 0 and solve. This zero-product rule will make our work with quadratic functions
much easier!
When a function is expressed in factored form (written as a product of linear factors), we can,
by the zero-product rule, determine its x-intercepts simply by setting each factor equal to 0.
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
Part III: Identify the key features and graph the quadratic function 𝒒(𝒙) = (πŸπ’™ βˆ’ πŸ”)(𝒙 βˆ’ πŸ•)
1. Determine the y-intercept by substituting 0 for x:
y-intercept: ( _____ , _____ )
2. Determine the x-intercepts by substituting 0 for π‘ž(π‘₯):
(Remember our zero-product rule!!)
2π‘₯ βˆ’ 6 = 0 π‘Žπ‘›π‘‘ π‘₯ βˆ’ 7 = 0
x-intercepts: ( ______ , ______ ) and ( _____ , ______ )
3. The symmetry of parabolas allows us to use the x-intercepts of a quadratic function to
determine its vertex.
In general, if a quadratic function has two x-intercepts, the x-coordinate of its vertex
must be midway between the two x-intercepts:
4. Using the intercepts you found above, determine the value that is midway between:
______ (let’s call it m)
Explain how you determined this value:
5. Calculate π‘ž(π‘š).
Identify the vertex ( π‘š , π‘ž(π‘š) )= ____________
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
6. Using the four key points you determined from #1-5,
complete the table of values below and graph the
function: 𝒒(𝒙) = (πŸπ’™ βˆ’ πŸ”)(𝒙 βˆ’ πŸ•)
Key Point
x-value
y-intercept
0
y-value
x-intercept
0
x-intercept
0
vertex
5
In general, when a quadratic function is presented in factored form, you can easily determine
the following to graph the function:
a. y-intercept
b. x-intercepts
c. vertex (using the point midway between the x-intercepts)
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
Part IV: You try it now!
Determine the key points for each function below. Then, use those four key points to graph
the function.
1. 𝑓(π‘₯) = (π‘₯ βˆ’ 1)(π‘₯ βˆ’ 3)
y-intercept: (_____ , ______)
x-intercepts: (_____ , ______) and ( _____ , ______)
vertex: ( _____ , ______)
2. 𝑔(π‘₯) = (π‘₯ + 1)(π‘₯ βˆ’ 3)
y-intercept: (_____, ______)
x-intercepts: (_____, ______) and (_____, ______)
vertex: (_____, ______)
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
3. β„Ž(π‘₯) = (π‘₯ + 1)(π‘₯ + 3)
y-intercept: (_____, ______)
x-intercepts: (_____, ______) and (_____, ______)
vertex: (_____, ______)
4. π‘˜(π‘₯) = βˆ’2(π‘₯ βˆ’ 1)(π‘₯ βˆ’ 3)
y-intercept: (_____, ______)
x-intercepts: (_____, ______) and (_____, ______)
vertex: (_____, ______)
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
Part V: Determine the vertex for each of the following quadratic functions.
1. 𝐹(π‘₯) = (400 – π‘₯)π‘₯
vertex is (_____, ______)
2. 𝐺(π‘₯) = βˆ’(400 βˆ’ π‘₯)(100 – π‘₯)
vertex is ( _____, ______ )
3. 𝐻(π‘₯) = π‘₯(π‘₯ βˆ’ 8)
vertex is ( _____, ______ )
4. 𝐽(π‘₯) = βˆ’(π‘₯ βˆ’ 2)(π‘₯ βˆ’ 13)
vertex is ( _____, ______ )
5. 𝐾(π‘₯) = (π‘₯ + 5)(π‘₯ + 9)
vertex is ( _____, ______ )
6. 𝐿(π‘₯) = (2π‘₯ + 6)(3π‘₯ βˆ’ 30)
vertex is ( _____, ______ )
7. 𝑀(π‘₯) = (240 βˆ’ 2π‘₯)(5π‘₯ + 100)
vertex is ( _____, ______ )
8. 𝑁(π‘₯) = (3π‘₯ βˆ’ 2)(π‘₯ + 7)
vertex is ( _____, ______ )
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
Part VI - Summary: When working with quadratic functions and graphing parabolas, it is
often important to determine the y-intercepts, the x-intercepts, and the vertex.
1. In general if a quadratic function is presented in factored form, explain how to
determine the vertex:
2. If you are given a general quadratic function in factored form as:
𝑓(π‘₯) = (π‘₯ βˆ’ π‘Ž)(π‘₯ βˆ’ 𝑏)
Identify the x-coordinate of the vertex of the function: ______________
3. Given the x-intercepts of a quadratic function:
(4  3, 0) and (4 ο€­ 3, 0)
Identify the x-coordinate of the vertex of the function: ______________
4. Suppose a quadratic function has only one x-intercept, what can you conclude about the
vertex?
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
Answer Key
Part I: Looking back at linear functions.
Consider the function: 𝑓(π‘₯) = 2π‘₯ – 6
4. Identify the y-intercept by substituting 0 for x:
( _______ , _______ )
5. Identify the x-intercept substituting 0 for 𝑓(π‘₯):
( _______ , _______ )
6. Using the intercepts, graph the function.
Calculating the x and y-intercepts of a function is a slick way to graph the function. We can use
this technique for other functions that are not linear, such as quadratic functions.
Part II: The Zero Product Rule
11. Determine 0 ο‚· 5 ο‚· 12 ο‚· 119 =____________
12. Determine (ο€­7) ο‚· (315) ο‚· (0) ο‚· (89) =____________
13. Determine (13)(21)(0) = ____________
14. What can you conclude from the example problems above?
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
15. If (π‘₯ βˆ’ 4)(π‘₯ + 8) = 0, find the value(s) for π‘₯. Show your work and explain how you got
your answers.
16. If we are given (π‘₯ βˆ’ 4)(π‘₯ + 8)(π‘₯ βˆ’ 2) and their product is 0, then one of the individual
factors MUST be 0.
Therefore, (π‘₯ βˆ’ 4)(π‘₯ + 8)(π‘₯ βˆ’ 2) = 0 when π‘₯ = 2, π‘₯ = _______, π‘Žπ‘›π‘‘ π‘₯ = ______.
17. Solve (π‘₯ βˆ’ 10)(π‘₯ + 6) = 0 π‘₯ = _______ π‘Žπ‘›π‘‘ π‘₯ = __________
18. Solve (2π‘₯ βˆ’ 8)(π‘₯ βˆ’ 12) = 0 π‘₯ = ______ π‘Žπ‘›π‘‘ π‘₯ = __________
19. Solve (3π‘₯ βˆ’ 2)(5 βˆ’ π‘₯) = 0
20. Solve (π‘₯ βˆ’ 𝐴)(π‘₯ βˆ’ 𝐡) = 0
π‘₯ = ______ π‘Žπ‘›π‘‘ π‘₯ = __________
π‘₯ = ______ π‘Žπ‘›π‘‘ π‘₯ = __________
In general, to determine when a product of linear factors is equal to 0, just set each individual
factor equal to 0 and solve. This zero-product rule will make our work with quadratic functions
much easier!
When a function is expressed in factored form (written as a product of linear factors), we can,
by the zero-product rule, determine its x-intercepts simply by setting each factor equal to 0.
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
Part III: Identify the key features and graph the quadratic function 𝒒(𝒙) = (πŸπ’™ βˆ’ πŸ”)(𝒙 βˆ’ πŸ•)
7. Determine the y-intercept by substituting 0 for x:
y-intercept: ( _____ , _____ )
8. Determine the x-intercepts by substituting 0 for π‘ž(π‘₯):
(Remember our zero-product rule!!)
2π‘₯ βˆ’ 6 = 0 π‘Žπ‘›π‘‘ π‘₯ βˆ’ 7 = 0
x-intercepts: ( ______ , ______ ) and ( _____ , ______ )
9. The symmetry of parabolas allows us to use the x-intercepts of a quadratic function to
determine its vertex.
In general, if a quadratic function has two x-intercepts, the x-coordinate of its vertex
must be midway between the two x-intercepts:
10. Using the intercepts you found above, determine the value that is midway between:
______ (let’s call it m)
Explain how you determined this value:
11. Calculate π‘ž(π‘š).
Identify the vertex ( π‘š , π‘ž(π‘š) )= ____________
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
12. Using the four key points you determined from #1-5,
complete the table of values below and graph the
function: 𝒒(𝒙) = (πŸπ’™ βˆ’ πŸ”)(𝒙 βˆ’ πŸ•)
Key Point
x-value
y-intercept
0
y-value
x-intercept
0
x-intercept
0
vertex
5
In general, when a quadratic function is presented in factored form, you can easily determine
the following to graph the function:
d. y-intercept
e. x-intercepts
f. vertex (using the point midway between the x-intercepts)
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
Part IV: You try it now!
Determine the key points for each function below. Then, use those four key points to graph
the function.
5. 𝑓(π‘₯) = (π‘₯ βˆ’ 1)(π‘₯ βˆ’ 3)
y-intercept: (_____ , ______)
x-intercepts: (_____ , ______) and ( _____ , ______)
vertex: ( _____ , ______)
6. 𝑔(π‘₯) = (π‘₯ + 1)(π‘₯ βˆ’ 3)
y-intercept: (_____, ______)
x-intercepts: (_____, ______) and (_____, ______)
vertex: (_____, ______)
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
7. β„Ž(π‘₯) = (π‘₯ + 1)(π‘₯ + 3)
y-intercept: (_____, ______)
x-intercepts: (_____, ______) and (_____, ______)
vertex: (_____, ______)
8. π‘˜(π‘₯) = βˆ’2(π‘₯ βˆ’ 1)(π‘₯ βˆ’ 3)
y-intercept: (_____, ______)
x-intercepts: (_____, ______) and (_____, ______)
vertex: (_____, ______)
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
Part V: Determine the vertex for each of the following quadratic functions.
9. 𝐹(π‘₯) = (400 – π‘₯)π‘₯
vertex is (_____, ______)
10. 𝐺(π‘₯) = βˆ’(400 βˆ’ π‘₯)(100 – π‘₯)
vertex is ( _____, ______ )
11. 𝐻(π‘₯) = π‘₯(π‘₯ βˆ’ 8)
vertex is ( _____, ______ )
12. 𝐽(π‘₯) = βˆ’(π‘₯ βˆ’ 2)(π‘₯ βˆ’ 13)
vertex is ( _____, ______ )
13. 𝐾(π‘₯) = (π‘₯ + 5)(π‘₯ + 9)
vertex is ( _____, ______ )
14. 𝐿(π‘₯) = (2π‘₯ + 6)(3π‘₯ βˆ’ 30)
vertex is ( _____, ______ )
15. 𝑀(π‘₯) = (240 βˆ’ 2π‘₯)(5π‘₯ + 100)
vertex is ( _____, ______ )
16. 𝑁(π‘₯) = (3π‘₯ βˆ’ 2)(π‘₯ + 7)
vertex is ( _____, ______ )
Math 2 (L1-2)
A.SSE.3, F.IF.8
Assessment Title: Factored Form of a Quadratic
Unit 3: Quadratic Functions: Working with Equations
Part VI - Summary: When working with quadratic functions and graphing parabolas, it is
often important to determine the y-intercepts, the x-intercepts, and the vertex.
5. In general if a quadratic function is presented in factored form, explain how to
determine the vertex:
6. If you are given a general quadratic function in factored form as:
𝑓(π‘₯) = (π‘₯ βˆ’ π‘Ž)(π‘₯ βˆ’ 𝑏)
Identify the x-coordinate of the vertex of the function: ______________
7. Given the x-intercepts of a quadratic function:
(4  3, 0) and (4 ο€­ 3, 0)
Identify the x-coordinate of the vertex of the function: ______________
8. Suppose a quadratic function has only one x-intercept, what can you conclude about the
vertex?