document.write( "Question 1132100: The sum of the first three terms of a G.P. is 42 and the fourth term exceeds the first by 42.
\n" ); document.write( "Find the values of the first term and the common ratio. \n" ); document.write( "

Algebra.Com's Answer #748988 by math_helper(2461) $\"\"$ $\"About$

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document.write( "(1)   \r\n" );
document.write( "(2)    
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\n" ); document.write( "So we have $\"++a+%2B+ar+%2B+ar%5E2+=+ar%5E3+-+a+\"$
\n" ); document.write( " $\"+1+%2B+r+%2B+r%5E2+=+r%5E3+-+1+\"$
\n" ); document.write( " $\"+1+%2B+r+%2B+r%5E2+=+%28r+-+1%29%28r%5E2+%2B+r+%2B+1%29+\"$
\n" ); document.write( " $\"++1+=+%28r+-+1%29+\"$
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\n" ); document.write( "\n" ); document.write( "Common ratio:
\n" ); document.write( " $\"+highlight%28+r+=+2+%29+\"$
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\n" ); document.write( "\n" ); document.write( "First term:
\n" ); document.write( "from (1): $\"+a+%2B+2a+%2B+4a+=+42+\"$ --> a = 6
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\n" ); document.write( " $\"++highlight%28+a+=+6+%29+\"$
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\n" ); document.write( "Check:
\n" ); document.write( "6 + (2)(6) + (4)(6) = 6 + 12 + 24 = 42 (ok)
\n" ); document.write( "8(6) - 6 = 48 - 6 = 42 (ok)\r
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