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Calculate.
о Са
9
Note: Cr = (-)!
n!
n

Calculate. о Са 9 Note: Cr = (-)! n! n-example-1
User Lucidquiet
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1 Answer

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_9C_4=(9!)/(4!5!)=(6\cdot7\cdot8\cdot9)/(2\cdot3\cdot4)=126

User Atomman
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