Page 58 - Algebra 1

L E9S S O N Evaluating and Comparing Algebraic Expressions
Warm Up
NewConcepts
1. Vocabulary When two numbers are divided, the result is called
(2)
Simplify.
. (quotient, product).
_43 2
the
52 3 2. x b · 3b x
3. 23 + 7 (3) _ (4)
53 ⎡⎤ 4. 2 2 5. 32 ÷ ⎣2 · (8 - 7)⎦
(4) 3 + 4 (7)
Example
1
Math Language
Evaluate means to substitute values for the variables and to simplify using the order of operations.
Example
2
Online Connection www.SaxonMathResources.com
Anyexpressioncontainingonlynumbersandoperationsisanumericexpression. An algebraic expression is an expression with variables and/or numbers that uses operations (e.g., +, -, ×, or ÷). An algebraic expression is also called a variable expression.
Evaluating Algebraic Expressions
Evaluate the expression when x = 3 and a = 1.
3x - 4x + ax
SOLUTION Substitute 3 for x and 1 for a in the expression. Then simplify.
3x - 4x + ax =3·3-4·3+1·3 = 9 - 12 + 3
=0
When the variables in algebraic expressions have exponents, it is helpful to write the value in parentheses.
Evaluating Algebraic Expressions with Exponents
Evaluate the expression for y = 2 and z = 4.
3(z - y)2 - 4y3
SOLUTION Substitute 2 for y and 4 for z in the expression. Then simplify. 3(z - y)2 + 4y3
= 3(4 - 2)2 - 4(2)3 = 3(2)2 - 4(2)3
= 3 · 4 - 4(8)
= 12 - (32)
= -20
Lesson 9 43