Straight Lines And Pair Of Straight Lines

Point $(-1,2)$ is changed to $(a, b)$, when the origin is shifted to the point $(2,-1)$ by translation of axes, Point $(a, b)$ is changed to $(c, d)$, when the axes are rotated through an angle of $45^{\circ}$ about the new origin, $(c, d)$ is changed to $(e, f)$, when $(c, d)$ is reflected through $y=x$. Then, $(e, f)=$