\mathbb{P}(X\in <-\infty,0> U <\frac{1}{y},+\infty}>)=1-\mathbb{P}(0\leq X\leq \frac{1}{y})=1-[F_X(\frac{1}{y})-\frac{1}{2}]=\frac{3}{2}-F_X(\frac{1}{y})