document.write( "Question 1071095: S30=5235 and A1=15
\n" ); document.write( "Find A30 and d \n" ); document.write( "

Algebra.Com's Answer #686119 by KMST(5328) $\"\"$ $\"About$

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$\"S%5Bn%5D=%28a%5B1%5D%2Ba%5Bn%5D%29%2An%2F2\"$
\n" ); document.write( "is my favorite way of calculating the sum.
\n" ); document.write( "Substituting,
\n" ); document.write( " $\"5235=%2815%2Ba%5B30%5D%29%2A30%2F2\"$
\n" ); document.write( " $\"10470=%2815%2Ba%5B30%5D%29%2A30\"$
\n" ); document.write( " $\"349=15%2Ba%5B30%5D\"$
\n" ); document.write( " $\"349-15=a%5B30%5D\"$
\n" ); document.write( " $\"highlight%28a%5B30%5D=334%29\"$
\n" ); document.write( "The formula for $\"a%5Bn%5D\"$
\n" ); document.write( "based on $\"a%5B1%5D\"$ and $\"d\"$ is
\n" ); document.write( " $\"a%5Bn%5D=a%5B1%5D%2B%28n-1%29%2Ad\"$
\n" ); document.write( "so, substituting we get
\n" ); document.write( " $\"334=15%2B%2830-1%29d\"$
\n" ); document.write( " $\"334=15%2B29d\"$
\n" ); document.write( " $\"334-15=29d\"$
\n" ); document.write( " $\"319=29d\"$
\n" ); document.write( " $\"319%2F29=d\"$
\n" ); document.write( " $\"highlight%28d=11%29\"$ \n" ); document.write( "

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