Two sides of a triangle are y=m1x and y=m2x. m1, m2 are the roots of the equation x2+ax−1=0. For all values of a, the orthocentre of the triangle lies at
y=m1x and y=m2x are two sides of triangle
x2+ax−1=0 has roots m1,m2
∴m1m2=−1
i.e. y=m1x & y=m2x lines are perpendicular to each other
So, orthocentre of right angle triangle lies at verticles of 90∘ angle
So, orthocentre of given triangle is (0,0)