To apply distributive property, first we need to identify the terms inside the parentheses. The terms are separated by a "+" or a "-".
In this case, the parentheses (3x + 1) has the terms:
"3x" plus "1"
Now to apply distributive property, we multiply each term and then add them, as in the parentheses:

The expression with the distributive property applied is 6x + 2