The equation of the directrix of the parabola x2−4x−3y+10=0 is
y=54
The given equation can be written as (x−2)2=3(y-2). Shifting the origin at (2,2) this equation reduces to X2=3Y, where x=X+2, y=Y+2.
The directrix of this parabola with reference to new axes is Y = -a, where a=34
⇒y−2=−34⇒y=54