In ΔABC, the equation of altitudes AM and BN are x+5y-3=0, x+y-k=0. If the altitude CL is given by 3x-y-1=0, then k= ______.
(1)
Solving the altitudes AM and CL, we get
Orthocentre=(12,12) lies on x+y-k=0⇒k=1