Show that the line `lx+my + n =0` is a
normal to the circle `S = 0` if and only if
`gl +mf = n`

Show that the line lx+my+n=0 is a normal to the circles S=0 iff gl+mf=n .

Show that the line lx+my+n=0 is a normal to the circles S=0 iff gl+mf=mn .

The line lx+my+n=0 is a normal to the parabola y^2 = 4ax if

The line lx+my+n=0 is a normal to the parabola y^(2)=4ax if

The condition that the line lx +my+n =0 to be a normal to y^(2)=4ax is

The condition that the line lx +my+n =0 to be a normal to y^(2)=4ax is

Show that the lines lx + my + n = 0 , mx + ny + l = 0 and nx + ly + m = 0 are concurrent, if l + m + n = 0.

Find the coodition that the straight line lx+my+n=0 is a normal to the circle x^(2)+y^(2)+2gx+2fy+c=0