document.write( "Question 1075313: determine the value of m so that 2m+1, m, and 5-3m form an arithmetic progression \n" ); document.write( "
Algebra.Com's Answer #689995 by Theo(13342)\"\" \"About 
You can put this solution on YOUR website!
if it's an arithmetic progression, then:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "An = A1 + (n-1)* d\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "this means that A2 = A1 + d and A3 = A1 + 2d\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "based on this, then:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "A2 - A1 = A1 + d - A1 = d\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "A3 - A2 = A1 + 2d - A1 - d which results in A3 - A2 = d\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "so, you have:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "A2 - A1 = d
\n" ); document.write( "A3 - A1 = d\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "in other words, the common difference is d and each succeeding term in the sequence is increased by the same value of d and each term subtracted from the term immediately above is is equal to d.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "your terms are:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "A1 = 2m + 1
\n" ); document.write( "A2 = m
\n" ); document.write( "A3 = 5 - 3m\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "A2 - A1 is therefore equal to m - 2m - 1 which is equal to -m - 1\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "A3 - A2 is therefore equal to 5 - 3m - m which is equal to 5 - 4m\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "since both -m - 1 and 5 - 4m are equal to d, then they are equal to each other and you get:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "-m - 1 = 5 - 4m\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "add 4m to both sides and add 1 to both sides sand you get:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "3m = 6\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "solve for m to get m = 2.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "check your sequence is if it correct using m = 2.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "our sequence will be:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "A1 = 2m + 1 = 4 + 1 = 5
\n" ); document.write( "A2 = m = 2
\n" ); document.write( "A3 = 5 - 3m = 5- 6 = -1\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "your arithmetic sequence is 5, 2, -1.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "your common difference is -3.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "everything checks out ok when m = 2.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );