copyrightŠamberpasillas2010
An expression is NOT an equation because it DOES NOT have an equal sign. There are 2 types of expressions.
5 + 84 Numerical 3x + 10 Algebraic Notice there are no equal signs in these expressions so they are not equations! copyrightŠamberpasillas2010
A numerical expression contains only numbers and symbols and NO LETTERS.
5 times 3 plus 8 (5•3) + 8
copyrightŠamberpasillas2010
An algebraic expression contains only numbers, symbols, and variables. It is sometimes referred to as a variable expression. The product of 3 and x The sum of m and 8 The difference of r and 2 copyrightŠamberpasillas2010
3x m+8 r-2
What is a variable? A variable represents an unknown value. 1) 4 + x
2) 10 –
3) 5y
4) 20
?
A variable can be any letter of the alphabet since it represents an unknown. copyrightŠamberpasillas2010
Word Phrases for multiplication are: The product of 5 and a number c
5 • c or 5c Seven times a number t
7 • t or 7t 6 multiplied by a number d
6 • d or 6d copyright©amberpasillas2010
The Placement rule for multiplication is: The product of 5 and a number c
5 • c or 5c Seven times a number t
7 • t or 7t 6 multiplied by a number d
6 • d or 6d copyright©amberpasillas2010
Always write the variable AFTER the number.
Evaluate means to find the value of an algebraic expression by substituting numbers in for variables.
m=2 6+m? 6+2 8 copyrightŠamberpasillas2010
Evaluate means to find the value of an algebraic expression by substituting numbers in for variables.
r=3 7+r? 7+3 10 copyrightŠamberpasillas2010
Evaluate the variable expression when n = 6. 1) n + 8
2) n − 2
6+8
6−2 4
14
Evaluate just means solve by substitution. copyright©amberpasillas2010
Evaluate the variable expression when n = 6. n 4) 3) 3n 6 6 6
3•6 18
1
Evaluate just means solve by substitution. copyrightŠamberpasillas2010
Evaluate the algebraic expression when n = 8. 56 1) n
2) 20 − n
20 − 8
56 8
12
7
copyright©amberpasillas2010
Evaluate the expression if a = 3 and b = 4. 1) 3a + b
3• 3+ 4 9+4 13
2) 2b − a
2•4−3 8−3
5
copyright©amberpasillas2010
Evaluate the expression if a = 3 and b = 4. 3) 2ab
2 • 3• 4 6•4
4) 5 + ab
5 + 3• 4 5 + 12 17
24
copyright©amberpasillas2010
Evaluate the expression if x = 5 and y = 3. 3x 1) y
2) x + y 2
2
5 +3 25 + 9 2
3• 5 3 15 3 5
34
copyrightŠamberpasillas2010
2
Take Out Your Study Guide!!! copyrightŠamberpasillas2010
#1
TYPES OF EXPRESSIONS
An expression is NOT an equation because it does not have an equal sign. There are 2 types of expressions. NUMERICAL EXPRESSION: Contains only numbers and symbols. Example: 5 • 3 + 4 ALGEBRAIC EXPRESSION: Contains numbers, symbols, and variables. Also known as a variable expression. Example: m + 8 A VARIABLE is a letter or symbol that represents a number. Example: x copyright©amberpasillas2010
#2
Evaluate if x = 3 and y = 4 2 ( x + y)
2
2(3 + 4) 2 2(7) 2(49) 98
2
Evaluate means solve. Show the substitution. Show your work down. Circle your answer.
Show your work one step at a time down. No equal signs! copyrightŠamberpasillas2010