Question

Va rog!!!!!!!!!!!!!!!!

Answer 1

Răspuns:

Explicație pas cu pas:

Answer 2

$\it 5C_x^3=C^4_{x+2}\ \Rightarrow\ 5\cdot\dfrac{x!}{3!(x-3)!}=\dfrac{(x+2)!}{4!(x+2-4)!}\ \Rightarrow\ \\ \\ \\\ \Rightarrow\ \dfrac{5}{6}\cdot\dfrac{(x-3)!(x-2)(x-1)x}{(x-3)!} =\dfrac{1}{24}\dfrac{(x-2)!(x-1)x(x+1)(x+2)}{(x-2)!}|_{\cdot\dfrac{24}{x(x-1)}}\ \Rightarrow\ \\ \\ \\\ \Rightarrow\ 20x-40=x^2+3x+2 \Rightarrow x^2-17x+42=0 \Rightarrow x^2-3x-14x+42=0\Rightarrow\\ \\ \\ \Rightarrow x(x-3)-14(x-3)=0 \Rightarrow (x-3)(x-14)=0 \Rightarrow x_1=3,\ \ x_2=14$