DBT IN STRAIGHT LINES : ptt5

A line 4x+y=1 through the point A(2,-7) meets the line BC whose equation is 3x-4y+1=0. Then the equation of line such that AB=AC is
Your Answer: Did Not Attempt
Correct Answer: 52x+89y+519=0
Score: 0
Explaination :

slope of BC=3/4, slope os AB=-4, let slope of AC be m
{ how is slope AB = -4}
{does da que say B is pt. of intersection of 2 lines???}

angle ABC=angle BCA

(-4-3/4)/(1+(-4).(3/4))=(3/4-m)/(1+3m/4)

gives m=-52/89