document.write( "Question 3840: the numbers a, b, c are the terms of a geometric sequence so that
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document.write( "a+b+c=35 and abc=1000\r
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document.write( "find a, b and c \n" );
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Algebra.Com's Answer #1679 by longjonsilver(2297)![]() ![]() You can put this solution on YOUR website! a nice little question :-)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let first term = a \n" ); document.write( "then second term = ar \n" ); document.write( "and third term = \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "where r is the common ratio.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "And we know that all 3 terms multiplied together = 1000. So,\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "--> ar = cube root of 1000 \n" ); document.write( "ie ar = 10.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "And ar, by definition is the number b. So we have one found.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Since abc = 1000 and b=10, then ac=100. We shall use this in a moment.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Also, a+b+c=35. So now this becomes a+c=25 or a=25-c. Now sub this into the ac=100, to give (25-c)c=100.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Multiplying this out, we get a quadratic, \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "a=5 \n" ); document.write( "b=10 \n" ); document.write( "c=20\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Common ratio is 2. \n" ); document.write( "and Adding them --> 35 \n" ); document.write( "multiplying them --> 1000.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "jon \n" ); document.write( " \n" ); document.write( " |