bivariate normal distribution - how do I even do this?

The bivariate distribution: Bivariate Normal Distribution -- from Wolfram MathWorld

The question states:

Let X and Y have the bivariate normal (3,5,2,4,0.5) distribution.

a)Specify the marginal distribution of X.

b)Specify the marginal distribution of Y.

I have no idea how to do this. Can someone help?

From my book the only thing I could establish was

X=3+2Z

Y=5+4(Z/2 + C*sqrt(3/4))

where Z and C are independent random variables, both distributed N(0,1).