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Equations with the Distributive Property

When an equation has parentheses, like 3(x+4)=273(x + 4) = 27, the first job is to get rid of them. The distributive property does that: multiply the number outside the parentheses by each term inside.

After you distribute, the parentheses are gone and what's left is a two-step equation you already know how to solve. Distribute first, then solve — that's the whole lesson.

Distribute first

3(x+4)3(x + 4) means three copies of the whole quantity x+4x + 4. The distributive property multiplies the 33 by each term inside: 3x+34=3x+123 \cdot x + 3 \cdot 4 = 3x + 12. So the equation 3(x+4)=273(x + 4) = 27 becomes 3x+12=273x + 12 = 27.

The most common mistake is multiplying only the first term — writing 3x+43x + 4 instead of 3x+123x + 12. The outside number multiplies every term inside the parentheses, not just the one it touches.

Distributing a negative

If the outside number is negative, its sign travels with the multiplication. 4(x2)-4(x - 2) becomes 4x+8-4x + 8: the 4-4 times xx gives 4x-4x, and the 4-4 times 2-2 gives +8+8. Both terms change, and a negative times a negative comes out positive.

A shortcut: divide both sides first

When the outside number divides evenly into the other side, you can divide both sides by it instead of distributing. In 3(x+4)=273(x + 4) = 27, dividing both sides by 33 gives x+4=9x + 4 = 9, so x=5x = 5.

Use whichever route you like — distributing always works, and the shortcut is nice when the division is clean.

Worked examples

Example 1: distribute a positive number

Solve 3(x+4)=273(x + 4) = 27.

Distribute the 33 to both terms3x+12=273x + 12 = 27
Subtract 1212 from both sides3x=153x = 15
Divide both sides by 33x=5x = 5
Check: 3(5+4)=3(9)=273(5 + 4) = 3(9) = 27

Answer: x=5x = 5

Example 2: a two-term inside expression

Solve 2(3x5)=262(3x - 5) = 26.

Distribute the 22 to both terms6x10=266x - 10 = 26
Add 1010 to both sides6x=366x = 36
Divide both sides by 66x=6x = 6

Answer: x=6x = 6

Example 3: distribute a negative number

Solve 4(x2)=20-4(x - 2) = 20.

Distribute the 4-4 — both signs change4x+8=20-4x + 8 = 20
Subtract 88 from both sides4x=12-4x = 12
Divide both sides by 4-4x=3x = -3

Answer: x=3x = -3

Try one yourself

Common questions

Do I always have to distribute first?

No. If the outside number divides evenly into the other side, dividing both sides by it is faster: 3(x+4)=273(x + 4) = 27 becomes x+4=9x + 4 = 9 in one move. But distributing works on every problem, so it's the safe default.

What happens when I distribute a negative number?

Every term inside the parentheses picks up the sign. 4(x2)-4(x - 2) is 4x+8-4x + 8, not 4x8-4x - 8 — the 4-4 times 2-2 is a positive 88. Sign errors here are the number one source of wrong answers in this topic.

What if there's more outside the parentheses, like 2(x+3)+5=192(x + 3) + 5 = 19?

Distribute first, then combine like terms: 2x+6+5=192x + 6 + 5 = 19 becomes 2x+11=192x + 11 = 19, so 2x=82x = 8 and x=4x = 4. Clearing the parentheses is always the opening move.

How do I check my answer?

Substitute it into the original equation, parentheses and all. For x=3x = -3: 4(32)=4(5)=20-4(-3 - 2) = -4(-5) = 20 is true, so the answer checks.

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