Write in Standard Form y=(x-3)(x+5)

$y = (x - 3) (x + 5)$

To write a polynomial in standard form, simplify and then arrange the terms in descending order.

$y = a x^{2} + b x + c$

Expand $(x - 3) (x + 5)$ using the FOIL Method.

Apply the distributive property.

$y = x (x + 5) - 3 (x + 5)$

Apply the distributive property.

$y = x \cdot x + x \cdot 5 - 3 (x + 5)$

Apply the distributive property.

$y = x \cdot x + x \cdot 5 - 3 x - 3 \cdot 5$

Simplify and combine like terms.

Simplify each term.

Multiply $x$ by $x$ .

$y = x^{2} + x \cdot 5 - 3 x - 3 \cdot 5$

Move $5$ to the left of $x$ .

$y = x^{2} + 5 \cdot x - 3 x - 3 \cdot 5$

Multiply $- 3$ by $5$ .

$y = x^{2} + 5 x - 3 x - 15$

Subtract $3 x$ from $5 x$ .

$y = x^{2} + 2 x - 15$