document.write( "Question 755622: In a GP the sum of the 2nd and 3rd terms is 12,and the sum of the 3rd and 4th terms is 60. Find the common ratio and the 1st term. \n" ); document.write( "

Algebra.Com's Answer #459743 by josgarithmetic(39618) $\"\"$ $\"About$

You can put this solution on YOUR website!
Geometric progression: $\"a\"$ , $\"ar\"$ , $\"ar%5E2\"$ , $\"ar%5E3\"$ ,...\r
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\n" ); document.write( "\n" ); document.write( " $\"ar%2Bar%5E2=12\"$ and $\"ar%5E2%2Bar%5E3=60\"$ \r
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\n" ); document.write( "\n" ); document.write( " $\"%28ar%5E2%2Bar%5E3%29%2F%28ar%2Bar%5E2%29=5\"$ which is simply dividing second equation by first equation
\n" ); document.write( " $\"%28r%5E2%2Br%5E3%29%2F%28r%2Br%5E2%29=5\"$
\n" ); document.write( " $\"%28r%2Br%5E2%29%2F%281%2Br%29=5\"$
\n" ); document.write( " $\"r%2Br%5E2=5%281%2Br%29\"$
\n" ); document.write( " $\"r%5E2%2Br=5r%2B5\"$
\n" ); document.write( " $\"r%5E2-4r-5=0\"$
\n" ); document.write( " $\"%28r%2B1%29%28r-5%29=0\"$ \r
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\n" ); document.write( "\n" ); document.write( "Either $\"r=-1\"$ or $\"r=5\"$ .\r
\n" ); document.write( "\n" ); document.write( "The best choice would probably be $\"highlight%28r=5%29\"$ .
\n" ); document.write( "We still need to find a solution for 'a'. \n" ); document.write( "

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