Warm Up ) 7x + 4 for x = 6 2.) 8y – 22 for y = 9 46 Evaluate each algebraic expression for the given value of the variables. ) 7x + 4 for x = 6 2.) 8y – 22 for y = 9 3.) 12x + for x = 7 and y = 4 4.) y + 3z for y = 5 and z = 6 46 50 8 y 86 23

Do Now Simplify the following expression: 3x (x + y – 3)

Writing Algebraic Expressions Objective: Be able to write an algebraic expression for a word phrase or write a word phrase for an expression.

Although they are closely related, a Great Dane weighs about 40 times as much as a Chihuahua. An expression for the weight of the Great Dane could be 40c, where c is the weight of the Chihuahua. When solving real-world problems, you will need to translate words, or verbal expressions, into algebraic expressions.

Notes In order to translate a word phrase into an algebraic expression, we must first know some key word phrases for the basic operations.

With a Partner, come up with 3 words or phrases that represent: Addition Subtraction Multiplication Division

Addition Phrases: More than Increase by Greater than Add Plus Sum

Subtraction Phrases: Decreased by Difference between Take Away Minus Less than

Multiplication Phrases: Product Times Multiply Groups of Twice or double Triple

Division Phrases: Quotient Divided by Split equally

Quantity Quantity: is defined as an amount, measure or number. Write this as an expression: x times the quantity of 5 subtracted from 9 Answer: x(9-5)

Notes Multiplication expressions should be written in side-by-side form, with the number always in front of the variable. 3a 2t 1.5c 0.4f

Notes Division expressions should be written using the fraction bar instead of the traditional division sign.

Examples Addition phrases: 3 more than x the sum of 10 and a number c a number n increased by 4.5

Examples Subtraction phrases: a number t decreased by 4 the difference between 10 and a number y 6 less than a number z

Examples Multiplication phrases: the product of 3 and a number t twice the number x 4.2 times a number e

Examples Division phrases: the number y divided by 2 2.5 divide g the quotient of 25 and a number b the number y divided by 2 2.5 divide g

Examples converting f feet into inches a car travels at 75 mph for h hours the area of a rectangle with a length of 10 and a width of w

Examples converting i inches into feet the cost for tickets if you purchase 5 adult tickets at x dollars each the cost for tickets if you purchase 3 children’s tickets at y dollars each