Simplify (a+3)(a-3)

$(a + 3) (a - 3)$

Step 1

Expand $(a + 3) (a - 3)$ using the FOIL Method.

Apply the distributive property.

$a (a - 3) + 3 (a - 3)$

Apply the distributive property.

$a \cdot a + a \cdot - 3 + 3 (a - 3)$

Apply the distributive property.

$a \cdot a + a \cdot - 3 + 3 a + 3 \cdot - 3$

Step 2

Simplify terms.

Combine the opposite terms in $a \cdot a + a \cdot - 3 + 3 a + 3 \cdot - 3$ .

Reorder the factors in the terms $a \cdot - 3$ and $3 a$ .

$a \cdot a - 3 a + 3 a + 3 \cdot - 3$

Add $- 3 a$ and $3 a$ .

$a \cdot a + 0 + 3 \cdot - 3$

Add $a \cdot a$ and $0$ .

$a \cdot a + 3 \cdot - 3$

Simplify each term.

Multiply $a$ by $a$ .

$a^{2} + 3 \cdot - 3$

Multiply $3$ by $- 3$ .

$a^{2} - 9$