How to solve 2 equations with 2 unknown variables and plot the result?

I have this code to solve 2 equations with 2 unknown variables. And there are 2 known variables that is in a range. It gives the result but only one, where I expect it to be in a range too. Also, I could not plot it.

%Parameters
xin=0.2; xout=0.1; Pr=0.3; qf=1;
x=0:0.1:1;
alpha=0:100:1000;
%For Cross-Flow Module (CF)
y=(1+(x+Pr).*(alpha-1))-((1+(x+Pr).*(alpha-1)).^2-(4.*alpha.*(alpha-1).*x.*Pr)).^0.5/(2.*Pr.*(alpha-1))

y = 1×11

1.0e+03 * -0.0001 0.0398 0.0997 0.1796 0.2795 0.3994 0.5393 0.6992 0.8791 1.0790 1.2989

%qfout-qf=-(1-Pr+((alpha-1).*(x-Pr.*y)))*a
%x-xin=(-(1/qf).*(alpha.*(x-(Pr.*y))*a)+(-x.*ln(qfout/qf))
syms a qfout
E=-(1-Pr+((alpha-1).*(x-Pr.*y)))*a==qfout-qf , (-(1/qf).*alpha.*(x-(Pr.*y))*a)+(-x.*log(qfout/qf))==x-xin;

E = 

S=solve(E,a,qfout)

S = struct with fields:
        a: 0
    qfout: 1

plot(alpha,a)

Error using plot
Data must be numeric, datetime, duration or an array convertible to double.

Answer 1

[KSSV]

You need to convert the sym class to double using double.

plot(double(alpha),double(E))

[Nabilla Dewi Septiani]

Thank you sir. I can plot it now

But how to get the value for each array? As I only got one result and it is zero