Hello! The property illustrated by this equation is the distributive property.
The distributive property is when you have a number being multiplied by a set of parenthesis with numbers inside of it (either being added or subtracted from each other). For example, (a + b) * c. The property states that the number being multiplied can be distributed to all the numbers inside the parenthesis. This would appear as (a + b) * c = ac + bc.
Note: this can only be done when a and b are being added or subtracted.
Hope this helps!