document.write( "Question 1127067: 5;x;y is an arithmetic sequence and x;y;81 is a geometric sequence.All terms in the sequence are integers.calculate the value of x and y. \n" ); document.write( "
Algebra.Com's Answer #743448 by htmentor(1343)\"\" \"About 
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A.S. 5, x, y
\n" ); document.write( "G.S. x, y, 81
\n" ); document.write( "Let d = the common difference of the A.S.
\n" ); document.write( "Thus:
\n" ); document.write( "x - 5 = d
\n" ); document.write( "y - x = d
\n" ); document.write( "y - 5 = 2d -> y - 5 = 2(x - 5) -> y = 2x - 5
\n" ); document.write( "So the terms of the G.S. are:
\n" ); document.write( "x, 2x - 5, 81
\n" ); document.write( "The common ratio r = (2x - 5)/x = 81/(2x - 5)
\n" ); document.write( "Solve for x:
\n" ); document.write( "(2x - 5)/x = 81/(2x - 5)
\n" ); document.write( "(2x - 5)^2 = 81x
\n" ); document.write( "4x^2 - 101x + 25 = 0
\n" ); document.write( "This can be factored as (4x - 1)(x - 25)
\n" ); document.write( "Since the terms are all integers, x = 25
\n" ); document.write( "Hence y = 2*25 - 5 = 45
\n" ); document.write( "Ans: x = 25, y = 45
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