document.write( "Question 1135371: The sum of the first three terms of a G.P. is 42 and the fourth term exceeds first term by 42. \n" ); document.write( "

Algebra.Com's Answer #752996 by greenestamps(13200) $\"\"$ $\"About$

You can put this solution on YOUR website!

\n" ); document.write( "Your post should contain a question. Although it is obvious what your question probably is, it would be more polite if you asked it, instead of making us guess.

\n" ); document.write( "(1) $\"a%2Bar%2Bar%5E2+=+42\"$
\n" ); document.write( "(2) $\"ar%5E3-a+=+42\"$

\n" ); document.write( " $\"ar%5E3-a+=+a%28r%5E3-1%29+=+a%28r-1%29%28r%5E2%2Br%2B1%29+=+42%28r-1%29+=+42\"$
\n" ); document.write( " $\"r-1+=+42%2F42+=+1\"$
\n" ); document.write( " $\"r+=+2\"$

\n" ); document.write( "Substituting in (2),

\n" ); document.write( " $\"a%288%29-a+=+42\"$
\n" ); document.write( " $\"7a+=+42\"$
\n" ); document.write( " $\"a+=+6\"$

\n" ); document.write( "The GP is 6, 12, 24, 48, ... \n" ); document.write( "

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