Distributive Property Formula

The Formula

a(b + c) = ab + ac

When to use: Three packs of (2 red + 4 blue) = (3 \times 2 red) + (3 \times 4 blue) = 6 red + 12 blue.

Quick Example

5(10 + 2) = 5 \times 10 + 5 \times 2 = 50 + 10 = 60 Easier than 5 \times 12 directly.

Notation

a(b + c) is shorthand for a \times (b + c); the factor distributes to each term inside

What This Formula Means

Multiplication distributes over addition: a(b + c) = ab + ac, linking two operations together.

Three packs of (2 red + 4 blue) = (3 \times 2 red) + (3 \times 4 blue) = 6 red + 12 blue.

Formal View

\forall a, b, c \in \mathbb{R}: a(b + c) = ab + ac \text{ and } (a + b)c = ac + bc

Worked Examples

Example 1

easy
Expand 4(x + 7).

Solution

  1. 1
    Identify the two terms inside the parentheses: x and 7.
  2. 2
    Distribute 4 to each term inside the parentheses: 4 \cdot x + 4 \cdot 7.
  3. 3
    Simplify: 4x + 28.

Answer

4x + 28
The distributive property states a(b + c) = ab + ac. Multiply the outside factor by each term inside the parentheses.

Example 2

medium
Expand and simplify 3(2x - 5) + 2(x + 4).

Common Mistakes

  • Only distributing to the first term inside the parentheses: 3(x + 4) = 3x + 4 instead of 3x + 12
  • Forgetting to distribute the sign: -(a + b) = -a + b instead of -a - b
  • Trying to distribute multiplication over multiplication: a(bc) \neq (ab)(ac)

Why This Formula Matters

Foundation of algebra; enables factoring and expanding expressions.

Frequently Asked Questions

What is the Distributive Property formula?

Multiplication distributes over addition: a(b + c) = ab + ac, linking two operations together.

How do you use the Distributive Property formula?

Three packs of (2 red + 4 blue) = (3 \times 2 red) + (3 \times 4 blue) = 6 red + 12 blue.

What do the symbols mean in the Distributive Property formula?

a(b + c) is shorthand for a \times (b + c); the factor distributes to each term inside

Why is the Distributive Property formula important in Math?

Foundation of algebra; enables factoring and expanding expressions.

What do students get wrong about Distributive Property?

Works forwards (distributing) and backwards (factoring): ab + ac = a(b+c) is equally valid.

What should I learn before the Distributive Property formula?

Before studying the Distributive Property formula, you should understand: multiplication, addition.

Want the Full Guide?

This formula is covered in depth in our complete guide:

Commutative, Associative, and Distributive Properties โ†’