document.write( "Question 399540: in an arithmetic sequence, a3=-8 and a17=48\r
\n" ); document.write( "\n" ); document.write( "find the 20th term for the sequence \n" ); document.write( "

Algebra.Com's Answer #284095 by rahulsoni001002(1) $\"\"$ $\"About$

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T3=-8, T17=48 and T20=?\r
\n" ); document.write( "\n" ); document.write( "Tn=a+(n-1)d
\n" ); document.write( "T3=a+(3-1)d
\n" ); document.write( "-8=a+2d......(1)\r
\n" ); document.write( "\n" ); document.write( "Tn=a+(n-1)d
\n" ); document.write( "T17=a+(17-1)d
\n" ); document.write( "48=a+16d.....(2)\r
\n" ); document.write( "\n" ); document.write( "subtracting (2) from (1)
\n" ); document.write( "48=a+16d
\n" ); document.write( "-8=a+ 2d
\n" ); document.write( "- - -
\n" ); document.write( "____________
\n" ); document.write( "56= 14d
\n" ); document.write( "d=4\r
\n" ); document.write( "\n" ); document.write( "-8=a+2d putting d=4
\n" ); document.write( "-8=a+2(4)
\n" ); document.write( "-8=a+8
\n" ); document.write( "a=8+8
\n" ); document.write( "a=16\r
\n" ); document.write( "\n" ); document.write( "now a=16, d=4 ,T20=?
\n" ); document.write( "Tn=a+(n-1)d
\n" ); document.write( "T20=16+(20-1)(4)
\n" ); document.write( " =16+(19)(4)
\n" ); document.write( " =16+76
\n" ); document.write( " =92
\n" ); document.write( "T20=92 \n" ); document.write( "

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