# What is the standard form of y=(x+3)(x^2 - 3x + 9) ?

May 23, 2016

$y = {x}^{3} + 27$

#### Explanation:

We have

$y = \left(x + 3\right) \left({x}^{2} - 3 x + 9\right)$ .

We need to expand this using the Distributive Property.

$y = \left(x + 3\right) \left({x}^{2} - 3 x + 9\right)$

$= x \cdot \left({x}^{2} - 3 x + 9\right) + 3 \cdot \left({x}^{2} - 3 x + 9\right)$ .

We multiply these through to get

$y = {x}^{3} - 3 {x}^{2} + 9 \cdot x + 3 \cdot {x}^{2} - 9 x + 27$ .

Collecting like terms we have

$y = {x}^{3} + 27$ .