Question

Обчисліть будь ласка

Answer 1

$\frac{ \frac{7!}{(7 - 2)!}( \frac{4!}{2!(4 - 2)!} + 2 \times \frac{7!}{2!(7 - 2)!} )}{6!} = \frac{ \frac{7!}{5!} ( \frac{4!}{2! \times 2!} + \frac{7!}{5!}) }{6!} = \\ = \frac{6 \times 7 \times (3! + 6 \times 7)}{6!} = \frac{7(6 + 42)}{5!} = \frac{7 \times 48}{2 \times 3 \times 4 \times 5 \times 6} = \frac{7}{15}$