Question

Потрібна допомога (☞ ͡ ͡° ͜ ʖ ͡ ͡°)☞(ू˃̣̣̣̣̣̣︿˂̣̣̣̣̣̣ ू)

Розв'яжіть систему​

Answer 1

Ответ:

$(1;-2)\\(15\frac{2}{3};5\frac{1}{3})$

Объяснение:

$\left \{ {{x-2y=5} \atop {x^2-2xy-3y^2=-7}} \right. \\\\x=5+2y\\(5+2y)^2-2y(5+2y)-3y^2=-7\\25+20y+4y^2-10y-4y^2-3y^2=-7\\-3y^2+10y+25+7=0\\-3y^2+10y+32=0\\D=b^2-4ac=100-4*(-3)*32=100+384=484\\\sqrt{484}=22\\y1=\frac{-b+\sqrt{D} }{2a} =\frac{-10+22}{-6} =\frac{12}{-6} =-2\\y2=\frac{-b-\sqrt{D} }{2a} =\frac{-10-22}{-6} =\frac{-32}{-6} =\frac{16}{3}\\\\\left \{ {{y1=-2} \atop {x1=5+2*(-2)=1}} \right. \\\left \{ {{y2=\frac{16}{3}=15\frac{1}{3} } \atop {x=5+2*\frac{16}{3}=15\frac{2}{3} }} \right.$