Let a, b and c be the 7^th, 11^th and 13^th terms respectively of a non-constant A.P. If these are also three consecutive terms of a G.P., then $${a \over c}$$ equal to :

Let the equations of two sides of a triangle be 3x $$-$$ 2y + 6 = 0 and 4x + 5y $$-$$ 20 = 0. If the orthocentre of this triangle is at (1, 1), then the equation of its third side is :

The number of all possible positive integral values of $$\alpha $$  for which the roots of the quadratic equation, 6x² $$-$$ 11x + $$\alpha $$ = 0 are rational numbers is :

Let A = {x $$ \in $$ R : x is not a positive integer}.

Define a function $$f$$ : A $$ \to $$  R   as  $$f(x)$$ = $${{2x} \over {x - 1}}$$,

then $$f$$ is :