Final answer:
The distributive property allows you to multiply 3 by 14 by multiplying 3 by 10 and adding it to 3 times 4.
Step-by-step explanation:
The property that allows you to multiply 3 by 14 by multiplying 3 by 10 and adding it to 3 times 4 is the distributive property. The distributive property states that for any numbers a, b, and c, a(b + c) = ab + ac. In this case, you are multiplying 3 by the sum of 10 and 4, which can be written as 3(10+4). Using the distributive property, you can multiply 3 by both 10 and 4 separately and then add the results together. This gives you 3(10) + 3(4) = 30 + 12 = 42.