document.write( "Question 338972: Please help me solve this equation: \r
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document.write( "determine the second and fifth terms in the expanison of (2x-3y)^5? \n" );
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Algebra.Com's Answer #242977 by jim_thompson5910(35256) ![]() You can put this solution on YOUR website! \r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "To expand this, we're going to use binomial expansion. So let's look at Pascal's triangle: \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" ); document.write( " \n" ); document.write( "\n" ); document.write( "Looking at the row that starts with 1,5, etc, we can see that this row has the numbers:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "1, 5, 10, 10, 5, and 1\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "These numbers will be the coefficients of our expansion. So to expand \n" ); document.write( "\n" ); document.write( "Write the first coefficient. Multiply that coefficient with the first binomial term \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Once that has been done, add up the terms like this:\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" ); document.write( "However, we're not done yet.\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" ); document.write( "\n" ); document.write( "Continue this until you reach the final term.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Notice how the exponents of \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So the fully expanded expression should now look like this:\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" ); document.write( " \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" ); document.write( " \n" ); document.write( "\n" ); document.write( "So \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "In other words, \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "From the last equation, we can see that the 2nd term is \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Shortcut: You can find the kth term of the expansion \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "If you need more help, email me at jim_thompson5910@hotmail.com\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Also, feel free to check out my tutoring website. \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Jim \n" ); document.write( " |