Factor the variable expression:

To factor the expression \(36x + 8y\), we can start by finding the greatest common factor (GCF) of the coefficients of the two terms.

1. The coefficients are 36 and 8.
2. The GCF of 36 and 8 is 4.

Now, we can factor out the GCF from the expression:

\[
36x + 8y = 4(9x + 2y)
\]

Thus, the factored form of the expression is:

\[
\boxed{4(9x + 2y)}
\]