document.write( "Question 1081850: Can you please help me evaluate these two expressions? Thank you.
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document.write( "expression 1 = ₉C₂
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document.write( "expression 2 = ₇₀C₃ \n" );
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Algebra.Com's Answer #695902 by math_helper(2461) You can put this solution on YOUR website! nCr = n!/((n-r)!*r!) (\"Combinations\" or ways to arrange objects when order doesn't matter) \n" ); document.write( "where: \n" ); document.write( " n! = n*(n-1)*(n-2)*…*3*2*1 (I leave off the *1 when solving problems, it doesn't change anything)\r \n" ); document.write( "\n" ); document.write( "— \n" ); document.write( "Expression 1: \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Because I've seen these before, if I were writing it out, I'd say to myself 9*8 (because 7, 6, …, 2 will cancel from the (9-2)! = 7! part), divided by 2!=2: \n" ); document.write( " \n" ); document.write( "—\r \n" ); document.write( "\n" ); document.write( "For expression 2, using the shortcut, \n" ); document.write( " \n" ); document.write( " |