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The equation of the parabola whose focus...

The equation of the parabola whose focus is (1,-1) and the directrix is `x+y+7=0` is (a).`x^2+y^2-2x y-18 x-10 y=0` (b).`x^2+y^2-18 x-10 y-45=0` (c).`x^2-18 x-10 y-45=0` (d).`x^2+y^2-2x y-18 x-10 y-45=0`

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`x^2+y^2-2xy-18x-10y-45=0`
Let P(x,y) be any point on the parabola whose focus is S(1,-1) and the directrix is `x+y+7=0`
Draw PM perpendicular to `x+y+7=0`.
Then, we have
`SP=PM` ...
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