Answer:

4m³n²–2mn–3n

Step-by-step explanation:

(3m³n²–6mn–n)–(–4mn+2n–m³n²)

= 3m³n²–6mn–n+4mn–2n+m³n²

= 3m³n²+m³n²–6mn+4mn–n–2n

= 4m³n²–2mn–3n

Hope it helps...

By #NiloyBarman