document.write( "Question 1088296: The 4th term of an AP is zero. Prove that the 25th term of the A.P. is three times the 11th term. \n" ); document.write( "

Algebra.Com's Answer #702553 by Fombitz(32388) $\"\"$ $\"About$

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$\"a%5B4%5D=a%5B1%5D%2B%28n-1%29d=a%5B1%5D%2B3d=0\"$
\n" ); document.write( "So,
\n" ); document.write( " $\"a%5B1%5D=-3d\"$
\n" ); document.write( "and
\n" ); document.write( " $\"a%5B25%5D=a%5B1%5D%2B%2825-1%29d\"$
\n" ); document.write( " $\"a%5B25%5D=-3d%2B24d\"$
\n" ); document.write( " $\"a%5B25%5D=21d\"$
\n" ); document.write( "and
\n" ); document.write( " $\"a%5B11%5D=a%5B1%5D%2B%2811-1%29d\"$
\n" ); document.write( " $\"a%5B11%5D=-3d%2B10d\"$
\n" ); document.write( " $\"a%5B11%5D=7d\"$
\n" ); document.write( "So then,
\n" ); document.write( " $\"a%5B25%5D=21d\"$
\n" ); document.write( " $\"a%5B25%5D=3%287d%29\"$
\n" ); document.write( " $\"a%5B25%5D=3%2Aa%5B11%5D\"$
\n" ); document.write( " \n" ); document.write( "

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