By using standard formulae, expand the following:

$\Big(\dfrac{1}{2}x + \dfrac{2}{3}y\Big)^2$

By using standard formulae, expand the following:

$\Big(3x + \dfrac{1}{2x} \Big)^2$

By using standard formulae, expand the following:

(3x²y + 5z)²

By using standard formulae, expand the following:

$\Big(3x - \dfrac{1}{2x} \Big)^2$