Simplify (y-1)(y+1)

$(y - 1) (y + 1)$

Step 1

Expand $(y - 1) (y + 1)$ using the FOIL Method.

Apply the distributive property.

$y (y + 1) - 1 (y + 1)$

Apply the distributive property.

$y \cdot y + y \cdot 1 - 1 (y + 1)$

Apply the distributive property.

$y \cdot y + y \cdot 1 - 1 y - 1 \cdot 1$

Step 2

Simplify terms.

Combine the opposite terms in $y \cdot y + y \cdot 1 - 1 y - 1 \cdot 1$ .

Reorder the factors in the terms $y \cdot 1$ and $- 1 y$ .

$y \cdot y + 1 y - 1 y - 1 \cdot 1$

Subtract $1 y$ from $1 y$ .

$y \cdot y + 0 - 1 \cdot 1$

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

$y \cdot y - 1 \cdot 1$

Simplify each term.

Multiply $y$ by $y$ .

$y^{2} - 1 \cdot 1$

Multiply $- 1$ by $1$ .

$y^{2} - 1$