document.write( "Question 1196659: What is the missing term of the geometric sequence {-3,_,-108}? \n" ); document.write( "

Algebra.Com's Answer #829601 by ikleyn(52803) $\"\"$ $\"About$

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document.write( "You are given the 1st and the 3rd terms of a geometric progression, and they ask you about the 2nd term.\r\n" );
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document.write( "In any geometric progression, any term, which has neighbors terms on the left and on the right, is the geometric mean of the neighbors terms\r\n" );
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document.write( "     = .\r\n" );
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document.write( "In your case,\r\n" );
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document.write( "     =  = = +/- 18.\r\n" );
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document.write( "Square root of a positive number has two values, one positive and one negative, \r\n" );
document.write( "so you have two possible values 18 and -18 for the term    in the middle.\r\n" );
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document.write( "Accordingly, there are 2 (two) possible progressions:\r\n" );
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document.write( "    one progression is  -3, 18, -108  with the common ratio -6,\r\n" );
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document.write( "    and another progression  -3, -18, -108  with the common ratio 6.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Two other tutors missed one solution in their posts, which is an error of their analyses.\r
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\n" ); document.write( "\n" ); document.write( "Therefore, I came to restore the truth and to teach you to analyze in a right way.\r
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