reduce number of variables !!

In the code bellow I want to organize variables of a1,a2,a3 into a vector. But unfortunately I faced lots of unexpected errors.

It would be kind of u to help me

Thanks in advance :)

syms a1 a2 a3
y=a1+a2+a3
z=matlabFunction(y)
a1=x(1)
a2=x(2)   
a3=x(3)
x=[1 2 3]
w=z(x)

Answer 1

[Walter Roberson]

z = matlabFunction(y, 'vars', [a1, a2, a3]);

The result will take a vector.