If the lines `ax+y+1 = 0, x + by +1 = 0 `and` x +y+c = 0` are concurrent , prove that `1/(1-a)+1/(1-b)+1/(1-c)=1`

If the lines ax + y + 1 = 0, x + by + 1 = 0 and x + y + c = 0 are concurrent then prove that, (1)/( 1-a) + (1) /( 1-b) + (1) /( 1-c) = .

If the lines a x+y+1=0,x+b y+1=0 and x+y+c=0 are concurrent (a!=b!=c!=1) , prove that 1/(1-a)+1/(1-b)+1/(1-c)=1 .

If the lines ax+y+1=0,x+by+1=0 and x+y+c=0 are concurrent (a!=b!=c!=1), prove that (1)/(1-a)+(1)/(1-b)+(1)/(1-c)=1

If the lines ax + 2y + 1 = 0, bx + 3y + 1 = 0, cx + 4y + 1 = 0 are concurrent, then a, b, c are in

The lines ax + 2y + 1 = 0, bx + 3y +1 =0 and cx + 4y + 1=0 are concurrent if a, b, c are in A.P.

If the lines ax+12y+1=0 bx+13y+1=0 and cx+14y+1=0 are concurrent then a,b,c are in

If the lines ax+12y+1=0, bx+13y+1=0 and cx+14y+1=0 are concurrent, then a,b,c are in:

If the lines a x+2y+1=0,b x+3y+1=0a n dc x+4y+1=0 are concurrent, then a ,b ,c are in