Question

прошу помогите 30 баллов

Answer 1

Ответ:

$\left\{\begin{array}{l}x\cdot y=20\\x^2-y^2=9\end{array}\right\ \ \left\{\begin{array}{l}x=\dfrac{20}{y}\\\dfrac{400}{y^2}-y^2=9\end{array}\right\ \ \left\{\begin{array}{l}x=\dfrac{20}{y}\\\dfrac{400-y^4}{y^2}=9\end{array}\right$

$\left\{\begin{array}{l}x=\dfrac{20}{y}\\\dfrac{400-y^4-9y^2}{y^2}=0\end{array}\right\ \ \left\{\begin{array}{l}x=\dfrac{20}{y}\\y^4+9y^2-400=0\ ,\ y\ne 0\end{array}\right\ \ \left\{\begin{array}{l}x=\dfrac{20}{y}\\y_1=-25\ ,\ y_2=16\end{array}\right$

$\left\{\begin{array}{l}x_1=-\dfrac{4}{5}\ ,\ x_2=\dfrac{5}{4}\\y_1=-25\ ,\ y_2=16\end{array}\right\\\\\\Otvet:\ (-0,8\ ;-25\ )\ ,\ (\ 1,25\ ;\ 16\ )\ .$