Here is the Distributive Property made simple.
When you have a number outside a number or numbers inside parentheses, you multiply whatever is inside the parentheses by the number outside the parentheses.
3( 7 + 5 +4) becomes 3 x7 + 3x5 +3 x 4
0r 21 +15 +12
You multiplied each of the numbers by the 3
If there is a variable, that is distributed also
3y(4 + 6) becomes 12 y +18y