Transcript Sec. 2-5: Absolute Value Functions & Graphs

Sec. 2-5:
Absolute Value Functions &
Graphs
• The graph of an absolute value function will look
like the letter “V”.
• The reason for this is because when you enter
both positive & negative values in for the “x”, the
y result will always be positive
• The key to graphing absolute value functions is
to determine the VERTEX first.
Do this by setting what’s INSIDE the
absolute value equal to zero…this will
give you the “x” value of the vertex. Put
that number back into the original
equation to get the “y” value.
• Finally, pick x values on either side of the vertex,
plug those values into your equation to find the
y’s. GRAPH.
Graph
y = 4|2x – 5| - 3
Set the 2x – 5 = 0 to find x = 5/2, then put the 5/2
back into the equation to see what “y” is.
Once you know the VERTEX, pick x values to the
left & right of the vertex “X” value to get your
points.
x
y
V: 5/2 -3
L: 0
17
R: 3
1
Try this one!
Y = -2|5 – x|
Get your vertex: 5 – x = 0… so x is 5.
Put 5 back in to find “y”: y = 0 so V: (5, 0)
x
y
V: 5
0
L: 4 -2
R: 6 -2
**If you pick numbers the same distance
from your vertex you’ll get a “nice” V.
x
V: 5
L: 4
R: 6
y
0
-2
-2