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Holt CA Course 1
7-4 Graphing Quadratic Functions
ReviewFor the function, find the value of y for x = 0, x = 4, and x = –5.
y = 6x – 3 –3, 21, –33
Holt CA Course 1
7-4 Graphing Quadratic Functions
Vocabulary
quadratic functionparabola
Holt CA Course 1
7-4 Graphing Quadratic Functions
A quadratic function is a function in which the greatest power of the variable is 2. The most basic quadratic function is y = nx2 where n ≠ 0.
The graphs of all quadratic functions have the same basic shape, called a parabola.
Holt CA Course 1
7-4 Graphing Quadratic Functions
Create a table for each quadratic function, and use it to graph the function.
A. y = x2 + 1
Additional Example 1: Graphing Quadratic Functions
Plot the points and connect them with a smooth curve.
x x2 + 1 y
–2
–1
0
1
2
(–2)2 + 1 5
(–1)2 + 1 2
(0)2 + 1 1
(1)2 + 1 2
(2)2 + 1 5
Holt CA Course 1
7-4 Graphing Quadratic Functions
B. y = x2 – x + 1
Additional Example 1: Graphing Quadratic Functions
Plot the points and connect them with a smooth curve.
x x2 – x + 1 y
–2
–1
0
1
2
(–2)2 – (–2) + 1 7
(–1)2 – (–1) + 1 3
(0)2 – (0) + 1 1
(1)2 – (1) + 1 1
(2)2 – (2) + 1 3
Holt CA Course 1
7-4 Graphing Quadratic Functions
A. y = x2 – 1
Check It Out! Example 1
Plot the points and connect them with a smooth curve.
x x2 – 1 y
–2
–1
0
1
2
(–2)2 – 1 3
(–1)2 – 1 0
(0)2 – 1 –1
(1)2 – 1 0
(2)2 – 1 3
Create a table for each quadratic function, and use it to make a graph.
Holt CA Course 1
7-4 Graphing Quadratic Functions
B. y = x2 + x + 1
Check It Out! Example 1
Plot the points and connect them with a smooth curve.
x x2 + x + 1 y
–2
–1
0
1
2
(–2)2 + (–2) + 1 3
(–1)2 + (–1) + 1 1
(0)2 + (0) + 1 1
(1)2 + (1) + 1 3
(2)2 + (2) + 1 7
Holt CA Course 1
7-4 Graphing Quadratic FunctionsLesson Quiz: Part I
Create a table for the quadratic function, and use it to make a graph.
1. y = x2 – 2
Holt CA Course 1
7-4 Graphing Quadratic FunctionsLesson Quiz: Part II
Create a table for each quadratic function, and use it to make a graph.
2. y = x2 + x – 6
Holt CA Course 1
7-4 Graphing Quadratic Functions
Lesson Quiz: Part III
3. The function y = 40t – 5t2 gives the height of
an arrow in meters t seconds after it is shot
upward. What is the height of the arrow after 5
seconds?
75 m
