algebraic expression examples

Section 1.2 – Algebraic Expressions and Models Numerical expression – numbers, operations, and grouping symbols 25 = 22222 5 facotrs of 2 Base – 2 Exponent – 5 Power – the expression 25 Example 1/ Evaluating Powers a. b. (-3)4 = -34 = ORDER OF OPERATIONS 1. ______________________________________________ 2. ______________________________________________ 3. ______________________________________________ 4. ______________________________________________ Example 2/ Using Order of Operations 1.) -4 + 2(-2 + 5)2 2.) -8 + 5(1 – (-3))3 2 to the 5th power Variable – a letter that is used to represent one or more numbers Algebraic Expression – an expression involving variables Example 3/ Evaluating an Algebraic Expression Evaluate –3x2 – 5x + 7 when x = -2 Example 4/ Writing and Evaluating a Real-Life Model You have $75 and are buying some CDs that cost $15 each. Write an expression that shows how much money you have left after buying n movies. Evaluate the expression when n = 2 and n = 3. SIMPLIFYING ALGEBRAIC EXPRESSIONS - To simplify algebraic expressions you must combine like terms. Like terms are parts that have the same variable with the same exponent. When combining like terms you add the coefficients of the like terms together. Like Terms Unlike Terms 2 2 6x , 2x 6x, 2x2 Example 5/ Simplifying by Combining Like Terms a. 7x + 4x b. 3n2 + n – n2 c. 2(x + 1) – 3(x – 4) Example 6/ Using a Real-Life Model You want to buy either a CD or a cassette as a gift for each of 10 people. CDs cost $13 each and cassettes cost $8 each. Write an expression for the total amount you must spend. Then evaluate the expression when 4 of the people get CDs. Example 7/ Write an expression for the total monthly cost of phone service if you pay a $5 fee and $0.08 per minute. Then, find the cost if you talk 6 hours during the month. HOMEWORK – ASSIGNMENT #2