How to get coefficients of a multi-variable polynomial of 2nd Degree?

Lets say the polynomial is a function of x, y and z,like 2x^2+xy+zx+y^2. What code should I write that returns exactly the coefficients of x^2? How exactly should I use the function "coeffs"? I have an array of multi-variable polynomials,and I just want the coefficient of (x^2) from them. Thanks

[Walter Roberson]

There are examples at http://www.mathworks.com/help/symbolic/coeffs.html