If P is a point on the circle x^2+y^2=4, Q is a point on the straight line 5 x+y+2=0 and x-y+1=0 is the perpendicular bisector of PQ, then 13 times…

If P is a point on the circle $\displaystyle x^2+y^2=4, \mathrm{Q}$ is a point on the straight line $\displaystyle 5 x+y+2=0$ and $\displaystyle x-y+1=0$ is the perpendicular bisector of PQ, then $\displaystyle 13$ times the sum of abscissa of all such points P is $\displaystyle \_\_\_\_$.