y=1-3x\\x^2+y^2+xy=3\end{cases}\\\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\\x^2+(1-3x)^2+x(1-3x)=3\\x^2+1-6x+9x^2+x-3x^2=3\\7x^2-5x-2=0\\x_{1,2}=\frac{5^+_-\sqrt{25+56}}{14}=\frac{5^+_-9}{14}\\\\x_1=1\ ;\ \ \ \ \ \ \ \ \ \ \ \ \ \ x_2=-\frac{2}{7}\\y_1=1-3=-2\ ;\ y_2=\frac{13}{7}" alt="\begin{cases}3x+y=1=>y=1-3x\\x^2+y^2+xy=3\end{cases}\\\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\\x^2+(1-3x)^2+x(1-3x)=3\\x^2+1-6x+9x^2+x-3x^2=3\\7x^2-5x-2=0\\x_{1,2}=\frac{5^+_-\sqrt{25+56}}{14}=\frac{5^+_-9}{14}\\\\x_1=1\ ;\ \ \ \ \ \ \ \ \ \ \ \ \ \ x_2=-\frac{2}{7}\\y_1=1-3=-2\ ;\ y_2=\frac{13}{7}" align="absmiddle" class="latex-formula">