D.E. of family of lines `ax+by+c=0` is

2a+b+2c=0(a,b,c in R), then the family of lines ax+by+c=0 is concurrent at

If 6a^2-3b^2-c^2+7ab-ac+4bc-0 , then the family of lines ax+by+c=0 is concurrent at

If 6a^2-3b^2-c^2+7ab-ac+4bc=0 , then the family of lines ax+by+c=0 is concurrent at

If 16a^(2)+25b^(2)-c^(2)=40ab, then the family of lines ax+by+c=0 is concurrent at the point(s)

If 4a^2+9b^2_c^2+12ab=0 then the family of straight lines ax+by+c=0 is concurrent at

If a^2-b^2-c^2-2ab=0 , then the family of lines ax+by+c=0 are concurrent at the points

If a^(2)+9b^(2)-4c^(2)=6ab, then the family of lines ax+by+c=0 are concurrent at:

If 2a+b+c=0 where a,b,c are the parameters,then the equation of a line belonging to both the family of lines ax+by+c=0 and bx+ay+c=0 is

If a, b, c are in A.P. then the family of lines ax+by+c=0 (A) passes through a fixed point (B) cuts equal intercepts on both the axes (C) forms a triangle with the axes with area = 1/2 |a+c -2b| (D) none of these