E N D
Topics • Subsets and Properties of Real Numbers • Evaluating and Simplifying Algebraic Expressions • Solving Linear Equations • Rewriting Formulas and Equations • Problem Solving Strategies and Models • Solving Linear Inequalities • Solving Absolute Value Equations and Inequalities
Subsets of Real Numbers • Natural Numbers: the set of numbers starting at 1 and increasing toward infinity; also called the “counting numbers” • Whole Numbers: the set of numbers starting at 0 and increasing toward infinity; the natural numbers and zero • Integers: the set of whole numbers and their opposites • Rational Numbers: the set of numbers that can be written as a ratio of integers • Irrational Numbers: the set of numbers that cannot be written as a ratio of integers • Real Numbers: the set of numbers, including both rational and irrational numbers, that exist in the real world
Order of Operations • Parentheses • Exponents • Multiplication • Division • Addition • Subtraction • *a note – if you cannot simplify the operation inside the parentheses, you might need to distribute or apply one of the other field properties to continue simplifying or solving.
Simplifying and Evaluating Expressions • Simplifying means combining all like terms and performing as many operations as possible. 9 + (3x – 2x)3 + 4x – 12 = 9 + 9x – 6x + 4x -12 = 7x – 3 • Evaluating means substituting a certain value for a variable and completing the remaining operations. Evaluate the above example at x = 5: 7x – 3 7(5) – 3 = 35 – 3 = 32
Solving Linear Equations • The goal of solving linear equations is to get the variable you are solving for alone on one side of the equal sign. • Use the Equality Properties to achieve this. • Example:
Writing Linear Equations Example: During one shift, a waiter earns wages of $20 and gets an additional 15% in tops on customers’ food bills. The waiter earns $105. What is the total of the customers’ food bills? Verbal Model: Income (dollars) = Wages (dollars) + Percent for tips · Food bills (dollars) Equation: 105 = 30 + .15 x Solve the Equation: 75 = .15x x = $500 The total of the customers’ food bills was $500
Rewriting Formulas and Equations • A formula is an equation that relates two or more quantities, usually represented by variables • To solve for a variable means to rewrite an equation as an equivalent equation in which the variable is on one side and does not appear on the other side. Example: Solve for y.