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Section 1.6 Multiplication and Division of Real Numbers 57 The coldest recorded temperature in Key West, Florida, is 41ºF. What is the difference between the coldest recorded temperature in Key West and the coldest recorded temperature in Barrow? 88. The record low temperature in New York City is 1 degree Fahrenheit below zero. The record low temperature in Palm Springs, California, is 23ºF. What is the difference between the record low temperatures of New York City and Palm Springs? Find the measure of the unknown angle of the given triangle. b a c 89. a = 41° b = 99° 90. b = 82°, c = 27° 91. Find the complement and the supplement of an angle whose measure is 69°. 92. Find the complement and the supplement of an angle whose measure is 18°. You Be the Teacher! Correct each student’s errors, if any. 93. Simplify the following expression: 1 5 - a-1 3 4 b . Elvernice’s work: 1 a-3 1 - 1 b = 5 4 5 - a- 7 4 b = 1 5 - 7 4 = 1 3 4 5 3 4 - 7 3 5 4 3 5 = 4 20 - 35 20 =- 31 20 . 94. Simplify the following expression:- 1 4 - (-3). Sherry’s work: - 1 4 3 3=- 1 4 3 3 1 =- 3 4 . Calculate It! Use a calculator to simplify each expression. Express answers in fractional form, when applicable. 95. 25.19 - 17.26 96. -2.45 - 5.68 97. - 5 6 - 5 98. 3 2 5 - 3 5 ���� ������������������������ Multiplication and Division of Real Numbers ▶ OBJECTIVES As a result of completing this section, you will be able to 1. Multiply real numbers. 2. Simplify exponential expressions. 3. Divide real numbers. 4. Evaluate algebraic expressions. 5. Solve real-life problems. 6. Troubleshoot common errors. Objective 1 ▶ Multiply real numbers. Ryan decides to play some poker. To play a hand, he must bet $5. He plays seven hands and does not win any of them. How much money did Ryan lose? To solve this problem, we need to know how to multiply positive and negative numbers together. If Ryan lost $5 for each of seven hands, he lost a total of $35. This can be determined mathematically by finding the product of 7 and -5. In this section, we will discuss multiplying and dividing real numbers along with real-life illustrations. Multiplying Real Numbers Multiplication of real numbers is just repeated addition. For example, 2(3) means that 3 is added two times or 3 + 3 = 6. Similarly, 3(2) means that 2 is added three times or 2 + 2 + 2 = 6. Using this concept, we can find the product 2(-3). This expression means that -3 is added two times or 2(-3) = (-3) + (-3) = -6 Now we need to find out what happens when two negative numbers are multiplied. Consider the product (-2)(-3). (-2)(-3) = -(2)(-3) = -2(-3) = -(-6) = 6 Rewrite negative 2 as the opposite of 2. Rewrite as the opposite of 2 times -3. The product of 2 and -3 is -6. The opposite of -6 is 6.


hendricks_beginning_algebra_1e_ch1_3
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