Simplify (y-9)(y+9)

$(y - 9) (y + 9)$

Step 1

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

Apply the distributive property.

$y (y + 9) - 9 (y + 9)$

Apply the distributive property.

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

Apply the distributive property.

$y \cdot y + y \cdot 9 - 9 y - 9 \cdot 9$

Step 2

Simplify terms.

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

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

$y \cdot y + 9 y - 9 y - 9 \cdot 9$

Subtract $9 y$ from $9 y$ .

$y \cdot y + 0 - 9 \cdot 9$

Add $y \cdot y$ and $0$ .

$y \cdot y - 9 \cdot 9$

Simplify each term.

Multiply $y$ by $y$ .

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

Multiply $- 9$ by $9$ .

$y^{2} - 81$