(3m²-n²)²-(m²-3n²)²=

(3m²-n²)²-(m²-3n²)²=
(3m²-n²)²-(m²-3n²)²=

(3m²-n²)²-(m²-3n²)²=
(3m²-n²)²-(m²-3n²)²
=(3m^2-n^2+m^2-3n^2)*(3m^2-n^2-m^2+3n^2)
=(4m^2-4n^2)*(2m^2+2n^2)
=8*(m^2-n^2)*(m^2+n^2) (1)
=8*(m^4-n^4)
=8m^4-8n^4 (2)
如果因式分解,则到(1)
如果化简,则到(2)