Answer:
[tex]\large\boxed{m=\dfrac{V+y-3x}{2}}[/tex]
Step-by-step explanation:
[tex]3x+2m-y=V\qquad\text{add}\ y\ \text{to both sides}\\\\3x+2m-y+y=V+y\\\\3x+2m=V+y\qquad\text{subtract}\ 3x\ \text{From both sides}\\\\3x-3x+2m=V+y-3x\\\\2m=V+y-3x\qquad\text{divide both sides by 2}\\\\\dfrac{2m}{2}=\dfrac{V+y-3x}{2}\\\\m=\dfrac{V+y-3x}{2}[/tex]