document.write( "Question 66130: the third and fourth terms of a sequence are 26 and 40. if the second differences are a constant 4, what are the first five terms of the sequence. \n" ); document.write( "

Algebra.Com's Answer #46855 by josmiceli(19441) $\"\"$ $\"About$

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1st term = a
\n" ); document.write( "2nd term = b
\n" ); document.write( "a, b, 26, 40 is the sequence
\n" ); document.write( "The first differences are
\n" ); document.write( "b-a, 26-b, 40-26
\n" ); document.write( "the 2nd differences are 4, so
\n" ); document.write( "(26 - b) - (b-a) = 4
\n" ); document.write( "14 - (26 - b) = 4
\n" ); document.write( "------------------------------
\n" ); document.write( "14 - 26 + b = 4
\n" ); document.write( "-12 + b = 4
\n" ); document.write( "b = 16
\n" ); document.write( "------------------------------
\n" ); document.write( "(26 - b) - (b-a) = 4
\n" ); document.write( "(26 - 16) - (16 - a) = 4
\n" ); document.write( "10 - 16 + a = 4
\n" ); document.write( "-6 + a = 4
\n" ); document.write( "a = 10
\n" ); document.write( "------------------------------
\n" ); document.write( "So, the sequence is
\n" ); document.write( "10,16,26,40
\n" ); document.write( "1st differences are
\n" ); document.write( "6,10,14
\n" ); document.write( "2nd differences are
\n" ); document.write( "4,4
\n" ); document.write( "------------------------------
\n" ); document.write( "Call the 5th term c
\n" ); document.write( "1st difference is
\n" ); document.write( "c - 40
\n" ); document.write( "2nd difference equals 4
\n" ); document.write( "c - 40 - 14 = 4
\n" ); document.write( "c - 54 = 4
\n" ); document.write( "c = 58
\n" ); document.write( "1st 5 terms are
\n" ); document.write( "10,16,26,40,58 \n" ); document.write( "

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