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 Elementary Math Fractions, Percentages, Word Problems, Equations, Inequations, Factorization, Expansion

 January 29th, 2018, 10:02 PM #1 Senior Member   Joined: Apr 2008 Posts: 194 Thanks: 3 Why is choice 3 the answer? (ex) Which of the following statements is true? (1) If P=Q, then P^n=Q^n where n is any integer (2) If P^n=Q^n, then P=Q where n is any integer (3) If P=Q, then P^n=Q^n where n is any positive integer (4) If P^n=Q^n, then P=Q where n is any positive integer my attempt If I let P and Q be 2 and let n be 1, these values satisfy all four choices. Next, I let P and Q be 2 and let n be -1. these values satisfy (1) and (2). So, I don't know why the answer key says (3) is the answer. Please help me. Thanks a lot. January 29th, 2018, 10:58 PM #2 Senior Member   Joined: Sep 2015 From: USA Posts: 2,553 Thanks: 1403 you can't prove anything by finding an example that works, you can only disprove something by finding an example that doesn't. (1) would be true except that 1/0 is undefined so that the statement isn't true when P=Q=0 when n is negative (2) isn't true for Q=-P and n even (3) is true (4) is false for the same reason as (2) Thanks from davedave January 30th, 2018, 10:49 PM #3 Senior Member   Joined: Apr 2008 Posts: 194 Thanks: 3 Thank you very much again, romsek. Tags answer, choice Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Similar Threads Thread Thread Starter Forum Replies Last Post shaharhada Algebra 1 December 13th, 2013 02:21 AM rage Algebra 2 September 14th, 2012 09:27 PM panky Algebra 1 October 10th, 2011 01:04 PM vjain1 Advanced Statistics 0 May 27th, 2010 05:20 AM ahhaaa Probability and Statistics 1 May 18th, 2010 04:23 PM

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