Final answer:
The distributive property allows us to multiply a number by a sum of terms by distributing the multiplication to each term inside the parentheses.
Step-by-step explanation:
The distributive property states that when you have a number multiplied by a sum of terms, you can distribute the multiplication to each term inside the parentheses. In this case, you can distribute the 20 to both x and 4.
20(x + 4) = 20*x + 20*4 = 20x + 80
Learn more about Applying the distributive property