Question

Нужно срочно!!!!!
Решите уравнение

Answer 1

$C^{k} _{n} = frac{n!}{k!(n - k)!}$

$frac{x!}{(x-1)!(x - x + 1)} (x-1)=frac{x!}{(x-1)!}(x-1)=frac{1*2*...*(x-1)*x}{1*2*...*(x-1)}(x-1) =$

$= x(x-1) = x^2 - x$

$x^2 - x = 30 x^2 - x - 30 = 0 D = 1 + 120 = 121 = 11^2 x_{1,2} = frac{-1 +- 11}{2} = -6; 5$