document.write( "Question 1137744: determine the coefficient of x^9 y^4 in the binomial expansion of (x + y)^13 power \n" ); document.write( "
Algebra.Com's Answer #755614 by MathLover1(20850)\"\" \"About 
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\n" ); document.write( "\n" ); document.write( "\"%28x+%2B+y%29%5E13+=13C0%2Ax%5E13%2Ay%5E0%2B13C1%2Ax%5E12%2Ay%5E1%2B13C2%2Ax%5E11%2Ay%5E2\"+\"13C3+%28x%29%5E10%2A%28y%29%5E3%2B13C4+%28x%29%5E9%2A%28y%29%5E4\"...\r
\n" ); document.write( "\n" ); document.write( "=>\"13C4+%28x%29%5E9%2Ay%5E4=715x%5E9%2Ay%5E4\"\r
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\n" ); document.write( "\n" ); document.write( "the coefficient of \"x%5E9%2A+y%5E4\" in the binomial expansion of \"%28x+%2B+y%29%5E13+\"power is \"715\"
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