Simplify (x-9)(x+9)

$(x - 9) (x + 9)$

Step 1

Expand $(x - 9) (x + 9)$ using the FOIL Method.

Apply the distributive property.

$x (x + 9) - 9 (x + 9)$

Apply the distributive property.

$x \cdot x + x \cdot 9 - 9 (x + 9)$

Apply the distributive property.

$x \cdot x + x \cdot 9 - 9 x - 9 \cdot 9$

Step 2

Simplify terms.

Combine the opposite terms in $x \cdot x + x \cdot 9 - 9 x - 9 \cdot 9$ .

Reorder the factors in the terms $x \cdot 9$ and $- 9 x$ .

$x \cdot x + 9 x - 9 x - 9 \cdot 9$

Subtract $9 x$ from $9 x$ .

$x \cdot x + 0 - 9 \cdot 9$

Add $x \cdot x$ and $0$ .

$x \cdot x - 9 \cdot 9$

Simplify each term.

Multiply $x$ by $x$ .

$x^{2} - 9 \cdot 9$

Multiply $- 9$ by $9$ .

$x^{2} - 81$