# What is the standard form of  y= ( x + 3)(x + 3) ?

$y = {x}^{2} + 6 x + 9$
To bring it into standard form, we have to expand the whole thing. We'll use the distributive property: $\left(a + b\right) \left(c + d\right) = a b + a d + b c + b d$ to expand it:
$y = \left(x + 3\right) \left(x + 3\right)$
$y = {x}^{2} + 3 x + 3 x + 9$
$y = {x}^{2} + 6 x + 9$