Symbolic operations

Hi,

I have a question regarding the usage of symbolics in Mathcad.

Say if i need to do an operation like this

a= x*x +y*y +z*x

b= x*y*z

i need the output of a*b+ a^2 in terms of x,y,z . .

My questions are as follows

how do we assign a&b (interms of x,y,z) ?

how do we get the output ?