Answer:
3(7 +4)
Step-by-step explanation:
Both numbers have a factor of 3, which means we can factor out that value.
Distributive property
The distributive property of multiplication over addition can be represented by the formula ...
a(b +c) = ab +ac
Application
In this case, we can rewrite the sum so that the common factor of 3 is visible:
21 +12 = 3·7 +3·4
Using the above form, we can see the correspondence ...
This means we can rewrite the sum as ...
21 +12 = 3(7 +4)
