Finally got it. The formula you entered was actually correct and the answer was y=(sqrt2 + 1)x. I watched a video and it explained it quite well.

Is the formula used for calculating an angle bisector?

Correct me if I'm wrong but looking around, I saw the formula

(A1x + B1y + C1)/√(A1^2 + B12) = + (A2 x+ B2y + C2)/√(A2^2 + B2^2)

with

L1 : A1x + B1y + C1 = 0

L2 : A2x + B2y + C2 = 0 .

Does this do the same thing? or is it a different formula