Tham khảo tài liệu 'geomegy review 2', ngoại ngữ, anh ngữ phổ thông phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | CHAPTER 8 Problem Solving This chapter reviews key problem-solving skills and concepts that you need to know for the SAT. Throughout the chapter are sample questions in the style of SAT questions. Each sample SAT question is followed by an explanation of the correct answer. Translating Words into Numbers To solve word problems you must be able to translate words into mathematical operations. You must analyze the language of the question and determine what the question is asking you to do. The following list presents phrases commonly found in word problems along with their mathematical equivalents A number means a variable. Example 17 minus a number equals 4. 17 - x 4 Increase means add. Example a number increased by 8 x 8 149 ------------------------------------ PROBLEM SOLVING More than means add. Example 4 more than a number 4 x Less than means subtract. Example 8 less than a number x 8 Times means multiply. Example 6 times a number 6x Times the sum means to multiply a number by a quantity. Example 7 times the sum of a number and 2 7 x 2 Note that variables can be used together. Example A number y exceeds 3 times a number x by 12. y 3x 12 Greater than means and less than means . Examples The product of x and 9 is greater than 15. x X 9 15 When 1 is added to a number x the sum is less than 29. x 1 29 At least means and at most means . Examples The sum of a number x and 5 is at least 11. x 5 11 When 14 is subtracted from a number x the difference is at most 6. x - 14 6 To square means to use an exponent of 2. 150 -------------------------------------- PROBLEM SOLVING ----------------------------------------------- Example The square of the sum of m and n is 25. m n 2 25 Practice Question If squaring the sum of y and 23 gives a result that is 4 less than 5 times y which of the following equations could you use to find the possible values of y a. y 23 2 5y 4 b. y2 23 5y 4 c. y2 23 2 y 4 5 d. y2 23 2 5y 4 e. y 23 2 y 4 5 Answer a. Break the problem into pieces while .
