Suppose that x takes on one of the values 0, 1, and 2. If for some constant k, P (X = i ) = k P ( X = i −1) for i = 1, 2 and P ( x = 0 ) = 1/7 , then the value of k is

Tangents are drawn to
the hyperbola
parallel to the straight line 2x − y =
1. One ofthe points of contact of tangents on the hyperbola is

then a vector
perpendicular to 
, and A(adj A) =

then a is
= x + y is