699. Form the equation for the coordinates of points $(x, y)$ that are equidistant from $(-2,2)$ and $(2,0)$.
$\triangleright$ We know that such points lie on the perpendicular bisector, which can be drawn on graph paper and then its equation can be found.

But we can also act algebraically: the equality of distances is equivalent to the equality of their squares, so the condition of equidistance can be rewritten as $(x+2)^{2}+(y-2)^{2}=(x-2)^{2}+y^{2}$, that is, $x^{2}+4 x+4+y^{2}-4 y+4=x^{2}-4 x+4+y^{2}$, or $8 x+4=4 y$, or $y=2 x+1 . \triangleleft$