Simplify (a-4)(a+4)

$(a - 4) (a + 4)$

Step 1

Expand $(a - 4) (a + 4)$ using the FOIL Method.

Apply the distributive property.

$a (a + 4) - 4 (a + 4)$

Apply the distributive property.

$a \cdot a + a \cdot 4 - 4 (a + 4)$

Apply the distributive property.

$a \cdot a + a \cdot 4 - 4 a - 4 \cdot 4$

Step 2

Simplify terms.

Combine the opposite terms in $a \cdot a + a \cdot 4 - 4 a - 4 \cdot 4$ .

Reorder the factors in the terms $a \cdot 4$ and $- 4 a$ .

$a \cdot a + 4 a - 4 a - 4 \cdot 4$

Subtract $4 a$ from $4 a$ .

$a \cdot a + 0 - 4 \cdot 4$

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

$a \cdot a - 4 \cdot 4$

Simplify each term.

Multiply $a$ by $a$ .

$a^{2} - 4 \cdot 4$

Multiply $- 4$ by $4$ .

$a^{2} - 16$