1.原式=(3a-4b)(7a-8b)-(11a-12b)(7a-8b)=(7a-8b)(3a-4b-11a+12b)=(7a-8b)(8b-8a)=8(7a-8b)(b-a)
2.原式=(m-n)^4+[m(m-n)^3-n(m-n)^3]=(m-n)^4+[(m-n)^4]=2(m-n)^4
1.原式=(3a-4b)(7a-8b)-(11a-12b)(7a-8b)=(7a-8b)(3a-4b-11a+12b)=(7a-8b)(8b-8a)=8(7a-8b)(b-a)
2.原式=(m-n)^4+[m(m-n)^3-n(m-n)^3]=(m-n)^4+[(m-n)^4]=2(m-n)^4