document.write( "Question 1051855: Find a and b if \"sum%28+ak%2Bb%2C+k=1%2C+n+%29+=+8n%5E2%2B11n\", given that \"sum%28+k%2C+k=1%2C+n+%29+=+%28n%28n%2B1%29%29%2F2\" \n" ); document.write( "
Algebra.Com's Answer #667325 by Bakr.R(8)\"\" \"About 
You can put this solution on YOUR website!
Thank you Edwin, that was actually extremely helpful and a unique method, it wasn't how I would tackle the problem, but the question did ask a series of questions prior (in my maths textbook) to force me to use the equation \"sum%28+k%2C+k=1%2C+n+%29+=+%28n%28n%2B1%29%29%2F2\" to find the answer (with the word \"Hence\"), so although your method works efficiently (and far more easily), a specific method was requested, and for those seeking that particular method, (I found during this question was being solved) here's how it was done.\r
\n" ); document.write( "\n" ); document.write( "\"sum%28+ak%2Bb%2C+k=1%2C+n+%29+=+8n%5E2%2B11n\"
\n" ); document.write( "With added coefficients, we can separate the terms each with its own sum, we reach:
\n" ); document.write( "\"sum%28+ak%2C+k=1%2C+n+%29+%2Bsum%28+b%2C+k=1%2C+n+%29+\"
\n" ); document.write( "Since we earlier found out \"sum%28+k%2C+k=1%2C+n+%29+=+%28n%28n%2B1%29%29%2F2\"
\n" ); document.write( "We may deduce that (with substitution)
\n" ); document.write( "\"a%2An%28n%2B1%29%2F2%2Bsum%28+b%2C+k=1%2C+n+%29+\"
\n" ); document.write( "and with coefficient b being the only term,
\n" ); document.write( "\"a%2An%28n%2B1%29%2F2%2Bbn+\" (since b is the only term and is a constant)
\n" ); document.write( "We expand terms
\n" ); document.write( "\"%28an%5E2%2Ban%29%2F2%2Bbn+=+8n%5E2%2B11n\"
\n" ); document.write( "We now follow a method of comparing coefficiants marked by the same variable, having each coefficient match its opposing equal value.
\n" ); document.write( "By splitting fractions to factorize to one variable of each, we have
\n" ); document.write( "\"an%5E2%2F2%2Ban%2F2%2Bbn+=+8n%5E2%2B11n\"
\n" ); document.write( "\"an%5E2%2F2%2Bn%28a%2F2%2Bb%29=+8n%5E2%2B11n\"
\n" ); document.write( "And so
\n" ); document.write( "\"an%5E2%2F2=8n%5E2\"
\n" ); document.write( "\"a%2F2=8\"
\n" ); document.write( "\"a=16\"
\n" ); document.write( "And moving to the second comparison,
\n" ); document.write( "\"n%28a%2F2%2Bb%29=11n\" We may substitute a
\n" ); document.write( "\"n%2816%2F2%2Bb%29=11n\"
\n" ); document.write( "\"8%2Bb=11\"
\n" ); document.write( "\"b=3\"
\n" ); document.write( "And with that relation we find a=16, b=3
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