Chapter 1: Sets, Operations and Algebraic Language 1.8: Translating Between English and Algebra Goal: To use algebra to represent or “model” problem situations, you must know how to translate commonly encountered verbal phrases and sentences into algebraic expressions and equations. Translating Algebraic Expressions When translating an algebraic expression into a verbal phrase, pay attention to the arithmetic operation that connects the variable to one or more numbers. n 5 Represents the sum of n and 5, or equivalently, 5 more than n n 3 Represents 3 subtracted from n, 3 less than n, or n diminished by 3 n 2 4n 1 2n 3 1 Represents n divided by 2 or one-half of n Represents 4 times n increased by 1 or, equivalently, 1 more than the product of 4 and n. Represents 2 times the sum of n and 3 increased by 1 Tim’s weight exceeds Sue’s weight by 13 If Sue weighs x pounds, then Tim weighs pounds. x+13 pounds. If Time weighs x pounds, then Sue weighs x13 pounds. The number of dimes exceeds 3 times the If there are x pennies, then there are 3x+2 number of pennies by 2. dimes Bill has 7 fewer dollars in his wallet then If there are x pennies, then there are three times the number Roger has in his 3x 7 dimes wallet. The sum of two numbers is 54. If x represents one of these numbers then 54x represents the other number. Victor is twice John’s age 8 years ago. If y is John’s current age, then y-8 represents John’s age 8 years ago so Victor’s current age is 2(y-8) Chapter 1, Section 1.6 Page 1 Chapter 1: Sets, Operations and Algebraic Language 1.8: Translating Between English and Algebra Translating Verbal Sentence An inequality is a mathematical statement that two quantities are not equal, as in 2x 1 7 e into an equation or an inequality, identify key phrases that can be translated directly into mathematical terms. Two times a number n increased by 5 is 17 Five times a number n exceeds 2 times that number by 21 When 2 is subtracted from a number n the result is at most 5 When twice a number x is increased by 5, the result is at least 27. Chapter 1, Section 1.6 Page 2 2n+5=17 5n=2n+21 n25 2x 5 27