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directrix&focuses in parabola

parabola

Find the eqn: of the parabola whose focus is (3,-4) & directrix is x-y+5=0 ?
help me

Use the distance formula and the formula for the distance from a point to a line.

$\sqrt{(x-3)^{2}+(x+4)^{2}}=\frac{|x-y+5|}{\sqrt{2}}$

Square both sides, then expand and simplify:

$(x-3)^{2}+(x+4)^{2}-\left(\frac{x-y+5}{\sqrt{2}}\right)^{2}=0$

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