Math141Sols1BS11

# Math141Sols1BS11 - QUIZ 1B SOLUTIONS(CHAPTER 1 MATH 141...

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QUIZ 1B - SOLUTIONS (CHAPTER 1) MATH 141 – SPRING 2011 – KUNIYUKI 60 POINTS TOTAL No notes or books allowed. A scientific calculator is allowed. You may assume that two-dimensional graphs are in the usual Cartesian xy -plane. Give exact answers, unless you are told to approximate. SHORTER PROBLEMS (42 POINTS TOTAL) 1) (6 points). Write the domain of f , where fx () = x + 2 x ± 3 , using interval form, the form using parentheses and/or brackets. x + 2 is real ± x + 2 ² 0 ± x ²³ 2 Now, x ± 3 = 0 ² x = 3 , so 3 is the only exclusion from the domain based on the denominator, which is not allowed to be 0. Here is a graph of the domain: In interval form, we have: ± 2, 3 ² ³ ) ´ 3, µ 2) (5 points). Find and box in the x -intercept(s) (if any) of the graph of y = 2 x 2 ± 5 x + 3 x ± 1 . If there are none, write “NONE.” We want the real zeros of 2 x 2 ± 5 x + 3 x ± 1 . Observe that 1 is the only real number not in the domain.

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Now, 2 x 2 ± 5 x + 3 x ± 1 = 0 ² 2 x 2 ± 5 x + 3 = 0 x ³ 1 () ² 2 x ± 3 x ± 1 = 0 x ³ 1 ² 2 x ± 3 = 0 or x ± 1 = 0 x ³ 1 by the ZFP (Zero Factor Property) ² x = 3 2 or The only x -intercept is 3 2 , or the point 3 2 ,0 ± ² ³ ´ µ .
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## This note was uploaded on 09/08/2011 for the course MATH 141 taught by Professor Staff during the Fall '11 term at Mesa CC.

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Math141Sols1BS11 - QUIZ 1B SOLUTIONS(CHAPTER 1 MATH 141...

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