Let, L1:3x−y+1=0 and L2:2x−3y+28=0.
Slope, m1=3=tanθ
⇒θ=60∘
⇒sinθ=23,cosθ=21

Now, equation of line passing through (2,3) and having slope 3 is,
21x−2=23y−3=r
⇒2x−3y+28=0
⇒4+r−9−233r+28=0
⇒(22−33)r+23=0
⇒r=33−246×33+233+2
⇒r=2346×133+2=4+63