Which one of the following curves is the orthogonal trajectory of straight lines passing through a fixed point (a,b) ?

A straight line passing through a point on a circle is

Find the equation of the straight lines passing through the following pair of point: (a,b) and (a+b,a-b)

Find the locus of the foot of the perpendicular drawn from the origin to the straight line which passes through the fixed point (a,b).

Find the slopes of the straight lines passing through the following pair is points (-a,b),(b,-a)

Find the locus of the foot of the perpendicular from the orign to a variable straighht line which always passes through the fixed point (a,b) .

If 3a+2b+c=0 the family of straight lines ax+by+c=0 passes through the fixed point (p, q) then p + q

The curve for which the normal at every point passes through a fixed point (h,k) is

If a+b+c=0 the straight line 2ax+3by+4c=0 passes through the fixed point

(xv) Which one of the following straight line passes through the origin ?

If the algebraic sum of perpendiculars from n given points on a variable straight line is zero then prove that the variable straight line passes through a fixed point