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Lesson 3.2 Extra Practice Answers 1. a) Minimum b) Maximum c) Maximum d) Minimum 6. a) $900 000 b) Maximum profit occurs when $20 000 is spent on advertising. c) $400 000 2. a) Minimum, 0 b) Minimum, ⫺11 c) Minimum, ⫺5 d) Maximum, 81 e) Minimum, 0 f ) Maximum, 14 7. $1739.58 3. a) R (x) ⫽ ⫺2x 2 ⫹ 12x, $18 000 b) R (x) ⫽ ⫺4x 2 ⫹ 16x, $16 000 c) R (x) ⫽ ⫺2x 2 ⫺ 8x, $8 000 d) R (x) ⫽ ⫺4.5x 2 ⫹ 1.7x, $482.30 4. a) ⫺4.31 b) 1.2 c) 1.8 d) ⫺1.69 9. Answers may vary. For example, the function is in standard form, so to find the minimum, first find the vertex. Completing the square would result in fractions that are more difficult to calculate than whole numbers. Since this function will factor, putting the function in factored form and averaging the zeros to find the x-coordinate of the vertex would be possible; however, there would still be fractions to work with. Using the graphing calculator to graph the function, then using CALC to find the minimum, would be the easiest method for this function. Copyright © 2008 by Thomson Nelson 5. a) P(x) ⫽ x 2 ⫹ 16x ⫺ 5, 8 b) P(x) ⫽ ⫺4x 2 ⫹ 24x ⫺ 1, 3 c) P(x) ⫽ ⫺2x 2 ⫹ 4x ⫺ 11, 1 d) P(x) ⫽ ⫺3x 2 ⫹ 24x ⫺ 24, 4 8. a) 79 m b) 4 seconds c) 15 metres 408 Functions 11: Lesson 3.2 Extra Practice Answers