Download Notes on

NOTES
Objective : Variables and Expressions
Date: ___________________
Vocabulary/Language of discipline
Variable: a symbol, usually a letter, which stands for different quantities.
Expression: a combination of variables and numbers representing a
mathematical relationship.
Function: rule that tells you how to perform one or more operations on a
number, called the input to produce a result called the output.
Notes/Rules/Steps/Procedures
 Variables are used in formulas and equations.
 Variables are usually letters such as x or n.
 In the equation 6k = 12; k is the variable
 When given a value for a variable, you are able to evaluate the expression.
Solve, if a=4
2c
= 2 x 12
= 24
b=6
c= 12
8a+c
= 8 x 4 + 12
= 32 + 12
= 44
d= 3
6db
=6x3x6
= 18 x 6
= 108
Evaluate the expression 3n (n must always be multiplied by 3)
Value of n
4
5
6
7
12
Expression Value
12
15
18
21
?
 In the above expression, the function rule is 3n
 Function rules tell you what to do to the input EVERY single time.
 Your answer is called the output.
Determine the function rule on the table below.
Value of X
1
2
3
7
11
Y
5
6
7
11
15
THINK: What do I do to x EVERY single time to get y?
Y= x +4
Examples/Patterns
ONE:
Evaluate the following expressions using
y=3
j=7
r=4
h= 12
n= 25
z= 10
a. 7y – j
b. 25z – 4r
c. 4n + 12
TWO:
Complete the table by evaluating the expression.
a. 7x
value of x
2
3
4
11
value of expression
b. y=3x + 2
1
2
value of x
3
8
value of expression
THREE:
X
Determine the function rule for each table below.
1
2
3
Y
2
5
4
6
10
2
3
7
Y=________________________________
X
Y
1
4
Y=_________________________________
5
6
10