Please see the work below.
Work Step by Step
since the dot product is not equal to zero, we know that u and v are not orthogonal to each other. In order to prove that u and v are parallel to each other, there should be a constant c such that (1,-1) = c(0,-1). However, since there is no constant to satisfy this inequality, it can be concluded that u and v are neither orthogonal nor parallel to each other.