Square of Difference: Using multiple rules

$(a+3b)^2-(3b-a)^2=\text{?}$

$12ab$

$(x+3)^2+(x-3)^2=\text{?}$

$2x^2+18$

$(x+y)^2-(x-y)^2+(x-y)(x+y)=\text{?}$

$x^2+4xy-y^2$

Find a X given the following equation:

$(x+3)^2+(2x-3)^2=5x(x-\frac{3}{5})$

$6$

$(x+3)^2=(x-3)^2$

$x=0$

$(\frac{2}{3}+\frac{m}{4})^2-\frac{4}{3}-(\frac{m}{4}-\frac{2}{3})^2=\text{?}$

$\frac{(\sqrt{2m}+2)(\sqrt{2m}-2)}{3}$

$(\frac{x}{3}-4)^2+x(\frac{\sqrt{8x}}{3}+2)(\frac{\sqrt{8x}}{3}-2)=\text{?}$

$x^2-6\frac{2}{3}x+16$