Question

if the two line l1 x + m1 y + n1 =0 and l2 x + m2 y + n2 =0 cut axes at con-cyclic points, then :-

Answer 1

`l_1:L_1x+M_1y+N_1=0`
`l_2:L_2x+m_2y+n_2=0`
A,B,C,D are points on circle.
Power of circle w.r.t origin is constant.
`|OB*OC|=|OA*OD|=C`
`|n_1/l_1*n_2/l_2|=|n_1/m_1*n_2/m_2|=C`
`|l_1l_2|=|m_1m_2|`
`l_1l_2=m_1m_2`.