For x2+y2+2gx+2fx+c=0
Chord of contact from (x1,y1) is
xx1+yy1+g(x+x1)+f(y+y1)+c=0
So, for x2+y2+6x+8y−11=0
Chord of contact from (x1,y1) is
xx1+yy1+3(x+x1)+4(y+y1)−11=0
1) For (1,1), equation is
x.1+y.1+3(x+1)+4(y+1)−11=0⇒4x+5y−4=0
2) For (0,0), equation is
x.0+y.0+3(x+0)+4(y+0)−11=0⇒3x+4y−11=0
3) For (1,−1), equation is
x.1+y.−1+3(x+1)+4(y−1)−11=0⇒4x+3y−12=0
4) For (−1,−1), equation is
x.−1+y.−1+3(x−1)+4(y−1)−11=0⇒2x+3y−18=0