Use this test determine whether the indicated products are competitive, complementary, or neither.
The daily demand equations for the sale of brand $A$ coffee and brand $B$ coffee in a supermarket are
$$
\begin{array}{l}
x=f(p, q)=200-5 p+4 q \\
y=g(p, q)=300+2 p-4 q
\end{array}
$$