POD#2 basicadvanced 2+ 4 × 5 − 3 2 = ( × 4) − 12 = 24 (4 + 8 × 4) − 12 (4 +32) − 12 (36) − × 5 − − 9 22− 9 13

Algebraic Expressions A variable is a symbol that represents an unknown quantity. An algebraic expression, such as n+2, is an expression that contains variables, numbers, and at least one operation.

The branch of mathematics that involves expressions with variables is called algebra. The numerical factor of a multiplication expression that contains a variable is called a coefficient. So, 6 is the coefficient of 6d. 6d 9st mn a 3 6 times d9 times s times tm times na times a times a

Example 1 Evaluate 2(n+3) if n= -4 2(n+3) = 2(-4+3) =2(-1) =-2

To translate a verbal phrase into an algebraic expression, the first step is to define a variable. When you define a variable, you choose a variable to represent an unknown quantity. Example: Leah has already read 20 pages of a book. She plans to read 5 pages each day from now on. Write an expression that represents the total number of pages she will have read in d days d

Whiteboard time Evaluate 8w − 2v if w=5 and v=3 8(5) − 2(3) 40 − 6 34

Evaluate 4y if y=3 4(3) (27)

An MP3 player costs $70 and song downloads cost $0.85 each. Write an expression that represents the cost of the MP3 player and x number of downloaded songs. Then find the total cost if 20 songs are downloaded x (20) = $87

POD #3 basicadvanced × 3 2 = (4 + 8 ÷ 2) 2 − 30 = 34 (4 + 4) 2 − 30 (8) 2 − − ×

Jenny earns $30 a day working part time at a supermarket. Write an algebraic expression to represent the amount of money she will earn in d days. Let’s practice 30d

A small company has $1000 to distribute to its employees as a bonus. How much money will each employee get? Let e represent the number of employees in the company. Let’s practice 1000 e

An electrician charges $45 per hour and spends $20 a day on gasoline. Write an algebraic expression to represent his earnings for one day. Let x represent the number of hours the electrician works in one day. Let’s practice 45x − 20

Fifteen less than twice a number Let’s practice 2x − 15

Three times a number, increased by seventeen Let’s practice 3x + 17

The product of nine and a number, decreased by six Let’s practice 9x − 6