Transcript 1-1 VARIABLES AND EXPRESSIONS Goals:  Evaluate variable expressions  Evaluate expressions containing exponents VOCABULARY  Variable – a letter used to represent numbers   Value – the number.

1-1 VARIABLES AND
EXPRESSIONS
Goals:
 Evaluate variable expressions
 Evaluate expressions containing
exponents
VOCABULARY

Variable – a letter used to represent numbers


Value – the number the variable is representing


Usually x, y or z
If x = 2 then 2 is the value of x.
Algebraic expression – collection of numbers,
variables and operations (+,-,*,÷)
2x
 3y + 1
 5k – 7

VARIABLE EXPRESSIONS
Expression
Meaning
Operation
8y
5(x)
8 times y
5 times x
Multiplication
Multiplication
6
w
6 divided by w
Division
v÷3
4+g
y–9
v divided by 3
4 plus g
y minus 9
Division
Addition
Subtraction
EVALUATING EXPRESSIONS
Evaluate - replace each variable with a number
to find the value of the expression
 Examples:

1.
8y when y = 3
24
2.
x + 7 when x = 12
19
3.
3x + 1 when x = 5
16
4.
2x + 5y when x = 4 and y = 8
48
VOCABULARY
Power – an expression that looks like 46
Exponent – the number of times a number is
multiplied by itself
Base – The number that is multiplied by itself
Square – a number raised to the second power
Cube – a number raised to the third power
READING AND WRITING POWERS
Power
101
52
Words
Ten to the first power
Meaning
10
Five to the second power
5 * 5 = 25
Five squared
43
Four to the third power
4 * 4 * 4 = 64
Four cubed
64
Six to the fourth power
x7
6 * 6 * 6 * 6 = 1296
x to the seventh power x * x * x * x * x * x * x
EVALUATING POWERS
1.
x3 when x = 5
125
2.
y2 when y = 7
49
3.
w5 when w = 2
32
EVALUATING POWERS
4.
(x + y)2 when x = 3 and y = 2
25
5.
x2 + y2 when x = 3 and y = 2
13
6.
2x3 when x = 4
128
7.
(2x)3 when x = 4
512
PRACTICE

On white boards
HOMEWORK

Worksheet – “1-1 Variables and Expressions”