How to use ezplot in MATLAB?

Question

I want to use ezplot in MATLAB, and because the function I want to plot consists of a large number of terms I may split it into smaller functions. Let me give an example of a small number of terms and it can be generalized to a large number of terms. To plot the function:

y2+xy+xy3+x+1=0

I let y1=x+1 and I write the following in MATLAB:

x=[0:1:5]
y1=x+1
ezplot('y.^2+x*y+x*y.^3+y1')

But there is an error. Please tell me how can I correct the error. Is it possible to use this feature (splitting the equation or function into a number of terms)?