Introduction to Quadratic
Functions
October 1st, 2015
2
f
(x)

x
Ex. 1: Graph the quadratic function
by plotting
points from the following table of values.
x
f(x)
-2
-1
0
1
2 does it make?
What shape
Does this graph have a minimum or a maximum?
Where is it?
What is the y-intercept? What is the x-intercept?
Vocabulary
Quadratic Function: A function that can be written in the form
2
.
f (x)  ax  bx  c
Parabola: The shape of the graph of a quadratic function.
Extrema: Minimum or maximum values of a function.
Minimum: The smallest y-value of a function.
Maximum: The largest y-value of a function.
x-intercept: A point where a function crosses the x-axis, found
by substituting in y=0.
y-intercept: A point where a function crosses the y-axis, found
by substituting in x=0.
f (x)  x  4
Ex. 2: Graph the quadratic function
plotting points from a table of values.
2
by
f (x)  x  6x  9
Ex. 3: Graph the quadratic function
by plotting points from a table of values.
2