## \$X~exp(1)\$,\$Cov(X,Y)=-2\$, \$E[Y]=-2\$, and \$Var(Y)=4\$. Find the cdf of Y

Let (X,Y) be a bivariate random variable, where X is an exponential r.v. with mean 1. $$Cov(X,Y)=-2$$, $$E[Y]=-2$$, and $$Var(Y)=4$$. Find the cdf of Y.

All I can get is $$E[XY]=-4$$ and $$E[Y^2]=8$$. how can these condition get the cdf of Y?