Whic of he ollowing equations are physically meanngful? knowing that $m$ is the is the velocity $[\frac{m}{s}],t$ is time $s,$ and $x$ is the distance $m.$ Select all that apply.

A$.\frac{1}{2}m{v}_1^2=2m{v}_2^2-3m{v}_3^2$

B$.2m_1=3m_2$

C$.3v=2\frac{x}{t}$