Question

determine o valor de x em: C x + 3,2 = 15

Answer 1

Vamos la

C(x + 3, 2) = 15

(x + 3)!/(x + 1)*2! = 15

(x + 3)*(x + 2) = 30

x² + 5x + 6 = 30

x² + 5x - 24 = 0

d² = 25 + 96 = 121, d = 11

x = (-5 + 11)/2 = 6/2 = 3