Question

решите уравнение помогите​

Answer 1

Ответ:

Объяснение:

$1)\ \\A_x^1=2\\\frac{x!}{(x-1)!} =2\\\frac{(x-1)!*x}{(x-1)!}=2\\x=2.$

$2)\\A_x^1=2x\\\frac{x^1}{(x-1)!}=2x\\\frac{(x-1)!*x}{(x-1)!}=2x\\ x=2x\\2x-x=0\\x=0\notin\ (x\geq 1).$

$3)\\A_x^2=2x\\\frac{x!}{(x-2)!} =2x\\\frac{(x-2)!*(x-1)*x}{(x-2)!}=2x\\(x-1)*x=2x\\x^2-x=2x\\x^2-3x=0\\x*(x-3)=0\\x_1=0\notin\ \ \ \\\ x_2=3.$

$4)\\A_x^2=3x+12\\\frac{x!}{(x-2)!}=3x+12\\ \frac{(x-2)!*(x-1)*x}{(x-2)!}=3x+12\\(x-1)*x=3x+12\\ x^2-x=3x+12\\x^2-4x-12=0\\D=64\ \ \ \ \sqrt{D}=8\\ x_1=-2\notin\\x_2=6.$