Equation of the tangent to the circle, at the point $(1, −1)$, whose centre is the point of intersection of the straight lines $x−y=1$ and $2x+y=3$ is :

Question

$\begin{array}{1 1}(1)\; 4x+y−3=0 \\(2)\; x+4y+3=0\\ (3)\; 3x−y−4=0 \\(4)\; x−3y−4=0 \end{array} $

Comments

how is the centre [4/3,1/3]?