解1题
原式=(-1/3m+3/4n)(1/3m+3/4n)
=(3/4n-1/3m)(3/4n+1/3m)
=(3/4n)²-(1/3m)²
=9/16n²-1/9m²
解2题
原式=(a²+b²)(a²-b²)(a^4+b^4)
=(a^4-b^4)(a^4+b^4)
=a^8-b^8
解1题
原式=(-1/3m+3/4n)(1/3m+3/4n)
=(3/4n-1/3m)(3/4n+1/3m)
=(3/4n)²-(1/3m)²
=9/16n²-1/9m²
解2题
原式=(a²+b²)(a²-b²)(a^4+b^4)
=(a^4-b^4)(a^4+b^4)
=a^8-b^8