Question

помогите решить срочно надо​

Answer 1

Ответ:

x+y=-3

Объяснение:

$\[\begin{array}{l}\left\{ \begin{array}{l}{x^3} + {y^3} = - 12\\xy(x + y) = - 5\end{array} \right.\\\left. \begin{array}{l}x + y = a\\xy = b\end{array} \right| = > \left\{ \begin{array}{l}{a^3} - 3ab = - 12\\ab = - 5\end{array} \right. = > \left\{ \begin{array}{l}3ab = {a^3} + 12\\ab = - 5\end{array} \right.\\\frac{{3ab}}{{ab}} = \frac{{{a^3} + 12}}{{ - 5}}\\3 = \frac{{{a^3} + 12}}{{ - 5}}\\ - 15 = {a^3} + 12\\{a^3} = - 27\\a = - 3\\x + y = - 3\end{array}\]$