# Evaluating Algebraic Expressions.

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Evaluating Algebraic Expressions

5 + 84 Numerical 3x + 10 Algebraic Expressions
An expression is NOT an equation because it DOES NOT have an equal sign. There are 2 types of expressions. Numerical 3x Algebraic Notice there are no equal signs in these expressions so they are not equations!

5 times 3 plus 8 (5•3) + 8 Expressions
A numerical expression contains only numbers and symbols and NO LETTERS. 5 times 3 plus 8 (5•3) + 8

An algebraic expression contains only numbers, symbols, and
Expressions An algebraic expression contains only numbers, symbols, and variables. It is sometimes referred to as a variable expression. The product of 3 and x x The sum of m and m + 8 The difference of r and r - 2

Expressions What is a variable? A variable represents an unknown value. 2) 10 – ? 1) 4 + x 4) 20 3) 5y A variable can be any letter of the alphabet since it represents an unknown.

5 • c or 5c 7 • t or 7t 6 • d or 6d Expressions
Word Phrases for multiplication are: The product of 5 and a number c Seven times a number t 6 multiplied by a number d 5 • c or 5c 7 • t or 7t 6 • d or 6d

Always write the variable AFTER the number.
Expressions The Placement rule for multiplication is: The product of 5 and a number c Seven times a number t 6 multiplied by a number d 5 • c or 5c Always write the variable AFTER the number. 7 • t or 7t 6 • d or 6d

m = 2 6 + m ? 6 + 2 8 Evaluate means to find the value of an
Expressions Evaluate means to find the value of an algebraic expression by substituting numbers in for variables. m = 2 6 + m ? 6 + 2 8

r = 3 7 + r ? 7 + 3 10 Evaluate means to find the value of an
Expressions Evaluate means to find the value of an algebraic expression by substituting numbers in for variables. r = 3 7 + r ? 7 + 3 10

Evaluate the variable expression when n = 6.
Expressions Evaluate the variable expression when n = 6. 1) 2) Evaluate just means solve by substitution.

Evaluate the variable expression when n = 6.
Expressions Evaluate the variable expression when n = 6. 3) 4) Evaluate just means solve by substitution.

Evaluate the algebraic expression when n = 8.
Expressions Evaluate the algebraic expression when n = 8. 1) 2)

Evaluate the expression if a = 3 and b = 4.
Expressions Evaluate the expression if a = 3 and b = 4. 1) 2)

Evaluate the expression if a = 3 and b = 4.
Expressions Evaluate the expression if a = 3 and b = 4. 3) 4)

Evaluate the expression if x = 5 and y = 3.
Expressions Evaluate the expression if x = 5 and y = 3. 2) 1)

TYPES OF EXPRESSIONS #1 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