document.write( "Question 974847: the sum of the second and third terms of a G.P is six times the fourth term. find the two possible values of the common difference. \n" ); document.write( "
Algebra.Com's Answer #596712 by amarjeeth123(569)\"\" \"About 
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Let the first term of the GP be a.
\n" ); document.write( "Let the common ratio be r.
\n" ); document.write( "second term=ar
\n" ); document.write( "third term=ar^2
\n" ); document.write( "fourth term=ar^3
\n" ); document.write( "We have ar+ar^2=6ar^3
\n" ); document.write( "1+r=6r^2
\n" ); document.write( "6r^2-r-1=0
\n" ); document.write( "6r^2-3r+2r-1=0
\n" ); document.write( "3r(2r-1)+1(2r-1)=0
\n" ); document.write( "(3r+1)(2r-1)=0
\n" ); document.write( "r=-1/3 or r=1/2
\n" ); document.write( "The two possible values of the common difference are r=-1/3 and r=1/2.
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