1.1 Evaluating Algebraic

Expressions

Use the correct order of operations to evaluate

algebraic expressions (AF 1.2)

Use algebraic terminology correctly (AF 1.4)

Objective:

Words to know…

Expression a mathematical phrase that contains operations, numbers, and/variables.

Evaluate

a letter that represents a value that can change or vary.

Numerical expression

contains only numbers

Variable

substitute a given number for the variable

contains one or more variables.Algebraic expression

Evaluating Algebraic

Expressions with One Variable

x – 5 for x = 12

12 – 5

7

Order of Operations

PEMDAS: 1. Parentheses 2. Exponents3. Multiply and Divide from left to right.4. Add and Subtract from left to right.

Evaluating Algebraic

Expressions with One Variable Substitute 4 for y.

Multiply.

2y + 1 for y = 4

2(4) + 1 8 + 1

Add.9

Evaluating Algebraic Expressions with One Variable

6(n + 2) – 4 for n = 5, 6, 7

6(5 + 2) – 4

6(7) – 4

42 – 4

386(6 + 2) – 4

6(8) – 4

48 – 4

446(7 + 2) – 4

6(9) – 4

54 – 4

50

n Substitute Parentheses Multiply Subtract567

SUMMARY:What is the Order of operations?

Evaluating Algebraic

Expressions with Two Variables

A. 4x + 3y for x = 2 and y = 1 4(2) + 3(1) 8 + 3 11

B. 9r – 2p for r = 3 and p = 5 9(3) – 2(5) 27 – 10 17

Physical science

application

Use the expression 1.8c + 32 to convert the temperature from degrees Celsius to degrees Fahrenheit.

Boiling point of water at sea level: 100°C

Substitute 100 for c.

Multiply.

1.8(100) + 32

180 + 32

1.8c + 32

Add.212

100°C = 212°F

Water boils at 212°F at sea level.

Classwork

Evaluate each expression for the given value(s) of the variables.1. 6x + 9 for x = 3 2. x + 14 for x = 83. 4x + 3y for x = 2, y = 34. y(27 – x) for x = 19, y = 65. If n is the amount of money in a savings account, then the expression n + 0.03n can be used to find the amount in the account after it has earned interest for one year. Find the total in the account after one year if $500 is the initial amount.

2722

1748

$515