ĐKXĐ: \(x;y\ne0\)
\(\Leftrightarrow\left\{{}\begin{matrix}x^2+\left(y-1\right)^2=85\\x=3y\end{matrix}\right.\)
Thế pt dưới lên trên:
\(\left(3y\right)^2+\left(y-1\right)^2=85\)
\(\Leftrightarrow10y^2-2y-84=0\)
\(\Rightarrow\left[{}\begin{matrix}y=3\Rightarrow x=9\\y=-\dfrac{14}{5}\Rightarrow x=-\dfrac{42}{5}\end{matrix}\right.\)