Question

Calculate.
12C4

Please help!

Answer 1

495

Explanation:

`{12 \: }^(c) \: 4 = (12!)/(4!(12 - 4)!) \\ = (12!)/(4! * 8!) \\ = (12 * 11 * 10 * 9 * 8!)/(4! * 8!)`

canceling 8! from both numerator and denominator.

`(12 * 11 * 10 * 9)/(4 * 3 * 2 * 1) \\ = 11 * 9 * 5\\ = 495`

Factorial of an integer, in mathematics, is the product of all positive integers less than or equal to the given positive integer.

Factorial of a number is denoted by placing an exclamation mark behind the number

Answer 2

`\quad\quad\quad\quad \\et\\et \\et\\etu\internetu\y\menyaa \la\la\la\la\\\\\\\\\\\\\dddddddddd\\\FFFFFFFF\\\\\\\\\\\\\ \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\displaystyle\ \Large \boldsymbol{} _(12)C_4=(12!)/(4!(12-4)!) =(12!)/(4!\cdot8!) =(12\cdot11\cdot10\cdot9\cdot8!\!\!\!\!\!\diagup)/(4!\cdot8! \!\!\!\!\!\diagup) = \\\\\\(12\!\!\!\!\!\diagup\cdot11\cdot10\cdot9)/(24\!\!\!\!\!\diagup_(\ \ 2))= (11\cdot10\cdot9)/(2) =\boxed{495}`