Dodaję stronami i otrzymuję [tex]x^2+2x=9[/tex].
[tex]x^2+2x=9\\x^2+2x+1=10\\\left(x+1\right)^2=10\\x+1=\sqrt{10} \vee x+1=-\sqrt{10}\\x=-1+\sqrt{10} \vee x=-1-\sqrt{10}\\\\2\left(-1+\sqrt{10}\right)-y=5 \vee 2\left(-1-\sqrt{10}\right)-y=5\\y=-2+2\sqrt{10}-5 \vee y=-2-2\sqrt{10}-5\\y=-7+2\sqrt{10} \vee y=-7-2\sqrt{10}\\\\\boxed{\left(x,y\right)\in\left\{\left(-1+\sqrt{10},-7+2\sqrt{10}\right),\left(-1-\sqrt{10},-7-2\sqrt{10}\right)\right\}}[/tex]
