True or false:
Not all relations are functions, but all functions are relations.
True
Evaluate f(x)=-3x if x=2
-6
Is it a function? {(2, 3), (4, 5), ( -2, 6)}
YES because x does not repeat
(0,1) (2,2) (4,3)
yes
2x +1 = 15
x =7
The set of inputs of a relation
Domain
Evaluate f(x)=2x+1 if x=-2
-3
Using the vertical line test does the graph of the points (1,3) and (1,5) represent a function?
False, the points fail the vertical line test
(0,0)(2,10) (3,20) (4, 30)
nope
-5t - 9 = 3t + 7
t = -2
The set of outputs of a function
Range
Evaluate f(x)=-3 - x if x=6
-9
Is it a function?
| x | y |
| 2 | 4 |
| 1 | 5 |
| 2 | 6 |
NO because x repeats
It can be any linear function
Many answers
(4d + 5)/7 = 2
9/4 or 2.25
A relation where every input has exactly one output.
function
Evaluate f(x)=-(4x+2) if x= banana
-(4banana + 2)
Is it a function?
YES because it passes the Vertical Line Test
y/3 - 3x = 1
yes
y = 9x +3
4(f -2) < 4f
All real numbers
The test to tell if a graph is a function
The Vertical Line Test
What is f(-2)?
-12
Is it a function? 
NO because it does not pass the Vertical Line Test
All Play:
On your whiteboards, rewrite this in the form
y=mx +b (If possible)
2(y + 3x) - 10 = 0
y = -3x + 5
|x + 10| > 3
x> -7 or x < -13