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# A circle of radius $\sqrt 20$ has the point $(-1,3)$. Its centre is on the line $x=-y$. Which of the following equations satisfies these conditions?

$(1) x^2+y^2-2x+2y -18=0$

$(2) x^2+y^2+2x-2y+18=0$

$(3) x^2+y^2+10x-10y+30=0$

$(4) x^2+y^2-10x+10y-30=0$