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Show that 9!3!6!+9!4!5!=10!4!6!

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Question

Show that `(9!)/(3!6!) + (9!)/(4!5!) = (10!)/(4!6!)`

Sum
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Solution

L.H.S. = `(9!)/(3!6!) + (9!)/(4!5!)`

= `(9!)/(3! xx 6 xx 5!) + (9!)/(4 xx 3! xx 5!)`

= `(9!)/(3!5!)[1/6 + 1/4]`

= `(9!)/(3!5!)[(4 + 6)/(6 xx 4)]`

= `(10 xx 9!)/(6 xx 5! xx 4 xx 3!)`

= `(10!)/(6!4!)`

= `(10!)/(4!6!)`

= R.H.S.

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Chapter 3: Permutations and Combination - Exercise 3.2 [Page 50]

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