# How do you multiply (2a+b)(a+2b)?

$\left(2 a + b\right) \left(a + 2 b\right)$
$2 {a}^{2} + 4 a b + a b + 2 {b}^{2}$
$2 {a}^{2} + 5 a b + 2 {b}^{2}$