# How do you multiply (3x + 7) ( 3x - 4)?

$3 {x}^{2} + 9 x - 28$
$\left(3 x + 7\right) \left(3 x - 4\right) \text{ }$ multiply out
$9 {x}^{2} - 12 x + 21 x - 28$
$9 {x}^{2} + 9 x - 28$