Simplify (a-10)(a+10)

$(a - 10) (a + 10)$

Step 1

Expand $(a - 10) (a + 10)$ using the FOIL Method.

Apply the distributive property.

$a (a + 10) - 10 (a + 10)$

Apply the distributive property.

$a \cdot a + a \cdot 10 - 10 (a + 10)$

Apply the distributive property.

$a \cdot a + a \cdot 10 - 10 a - 10 \cdot 10$

Step 2

Simplify terms.

Combine the opposite terms in $a \cdot a + a \cdot 10 - 10 a - 10 \cdot 10$ .

Reorder the factors in the terms $a \cdot 10$ and $- 10 a$ .

$a \cdot a + 10 a - 10 a - 10 \cdot 10$

Subtract $10 a$ from $10 a$ .

$a \cdot a + 0 - 10 \cdot 10$

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

$a \cdot a - 10 \cdot 10$

Simplify each term.

Multiply $a$ by $a$ .

$a^{2} - 10 \cdot 10$

Multiply $- 10$ by $10$ .

$a^{2} - 100$