因式分解 1.-4m^3-16m^2+8m 2.6a(b-a)^2-2(a-b)^3 3.6(x-30^2+3x-9 4.(3a-4b)(7a-8b)+(11a+2b)(8b-7a)

题目

因式分解 1.-4m^3-16m^2+8m 2.6a(b-a)^2-2(a-b)^3 3.6(x-30^2+3x-9 4.(3a-4b)(7a-8b)+(11a+2b)(8b-7a)

答案

1.-4m^3-16m^2+8m
=-4m(m^2+4m-2)
2.6a(b-a)^2-2(a-b)^3
=2(a-b)^2[3a-(a-b)]
=2(a-b)^2(2a+b)
3.6(x-3)^2+3x-9
=3(x-3)[2(x-3)+3]
=3(x-3)(2x-3)
4.(3a-4b)(7a-8b)+(11a+2b)(8b-7a)
=-(3a-4b)(8b-7a)+(11a+2b)(8b-7a)
=(8b-7a)[-(3a-4b)+11a+2b]
=(8b-7a)(8a+6b)
=2(8b-7a)(4a+3b)