Exercise 23 Page 86

We are given that the temperature inside an iceberg ranges from - 20^(∘) Celsius to - 15^(∘) Celsius. If we let C be the temperature, C must be greater than or equal to - 20 and less than or equal to - 15. C≥ - 20 and C ≤ - 15 The solution set to this compound inequality is given by the numbers that are between -20 and -15. -20 ≤ C ≤ -15 Since we are asked to find this temperature in degrees Fahrenheit, we will use the formula to convert degrees Celsius to degrees Fahrenheit. C=5/9(F-32) We can now substitute the right-hand side of this equation for C in our inequality. -20 ≤ 5/9(F-32) ≤ -15 Let's now solve this inequality for F.

-20 ≤ 5/9(F-32) ≤ -15

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Solve for F

Multiply each expression by 9

-180≤ 5(F-32) ≤ -135

Divide each expression by 5

-36 ≤ F-32 ≤ -27

Add 32 to each expression

-4 ≤ F ≤ 5