Problem using polyfit and syms in a for loop

Here is my code.

Z=[3 1];

for i=1:length(Z);

syms a

x=5*a-Z(:,i)

A(i)=solve(x,a);

syms b

y=3*a+Z(:,i)

B(i)=solve(y,b);

A(i)=Z(i)+2;

B(i)=Z(i)-7;

xfit=[0 1];

yfit1(:,i)=[A(i),B(i)]

pfit1(:,i)=polyfit(xfit1,yfit1(:,i),1);

pval1(i,:)=polyval(pfit1(i,:),xfit1);

The error message I am getting is:

Error using polyval: Inputs must be floats, namely single or double.

I tried running a similar code and without the syms part and the code worked fine. How do I get my code to work with syms?

[Image Analyst]

Here is how to format your code