(1)8a^2-2ab
(2)-3ma^3+6ma^2-12ma
(3)121-a^2
(4)25a^2-20ab+4b^2
(5)7x^2y^2-63x^2z^2
(6)9ax^2-24axy+16ay^2
(7)49(x-2)^2-25(x-3)^2
(8)3a(x^2+4)^2-48ax^2
(9)12ab^2(y-x)+9b^3(x-y)+4a^2b(x-y)
(10)4a^2b^2-(a^2+b^2)^2
(11)(x+2y)^3-(x+2y)
(12)x^2(2x-5)+4(5-2x)
(13)4a(x+3y)^2+12a(x+3y)+9a
(14)3a(x^2+4)^2-48ax^2
(1)8a^2-2ab
=2a(4a-b)
(2)-3ma^3+6ma^2-12ma
=-3ma(a^2-2a+4)
=-3ma(a-2)^2
(3)121-a^2
=11^2-a^2
=(11-a)(11+a)
(4)25a^2-20ab+4b^2
=(5a-2b)^2
(5)7x^2y^2-63x^2z^2
=7x^2(y^2-z^2)
=7x^2(y-z)(y+z)
(6)9ax^2-24axy+16ay^2
=a(9x^2-24xy+16y^2)
=a(3x-4y)^2
(7)49(x-2)^2-25(x-3)^2
=[7(x-2)-5(x-3)][7(x-2)+5(x-3)]
=(7x-14-5x+15)(7x-14+5x-15)
=(2x+1)(12x-29)
(8)3a(x^2+4)^2-48ax^2
=3a[(x^2+4)^2-16x^2]
=3a[(x^2+4-4x)][(x^2+4+4x)]
=3a(x-2)^2(x+2)^2
(9)12ab^2(y-x)+9b^3(x-y)+4a^2b(x-y)
=b(x-y)(-12ab+9b^2+4a^2)
=b(x-y)(2a-3b)^2
(10)4a^2b^2-(a^2+b^2)^2
=[2ab-(a^2+b^2)](2ab+a^2+b^2)
=-(a^2-2ab+b^2)(a+b)^2
=-(a-b)^2(a+b)^2
(11)(x+2y)^3-(x+2y)
=(x+2y)[(x+2y)^2-1][(x+2y)^2+1]
=(x+2y)(x+2y+1)(x+2y-1)
(12)x^2(2x-5)+4(5-2x)
=x^2(2x-5)-4(2x-5)
=(2x-5)(x^2-4)
=(2x-5)(x-2)(x+2)
(13)4a(x+3y)^2+12a(x+3y)+9a
=a[4(x+3y)^2+12(x+3y)+9]
=a[2(x+3y)+3]^2
=a(2x+6y+3)^2
(14)3a(x^2+4)^2-48ax^2
=3a[(x^2+4)^2-16x^2]
=3a[(x^2+4-4x)][(x^2+4+4x)]
=3a(x-2)^2(x+2)^2
1) 2a(4a-b)
2)-3ma(a^2-2a+4)
3)(11+a)(11-a)
4)(5a-2b)^2
5)7x^2(y^2-18z^2)
6)a(3x-4y)^2
7)(12x-29)(2x+1)
8)3a(x^2-4)^2
9)(x-y)(4a^2b+9b^3-12ab^2)
10)-(a^2-b^2)^2
11)(x+2y)(x^2+4xy+4y^2-1)
12)(2x-5)(x^2-4)
13)a[2(x+3y)+3a]^2
14)3a(x^2-4)^2
1、8a²-2ab=2a(4a-b)
2、-3ma³+6ma²-12ma=-3ma(a²-2a+4)
3、121-a²=11²-a²=(11+a)(11-a)
4、25a^2-20ab+4b^2=(5a)²-2×(5a)×(2b)+(2b)²=（5a-2b）²
5、7x²y²-63x²z²=7x²(y²-9z²)=7x²(y+3z)(y-3z)
6、9ax^2-24axy+16ay^2=a(9x²-12xy+16y²)=a(3x-4y)²
7、49(x-2)²-25(x-3)²=[7(x-2)+5(x-3)][7(x-2)-5(x-3)]=(12x-29)(2x+1)
8、3a(x^2+4)^2-48ax^2=3a[(x²+4)²-16x²]=3a(x²+4+4x)(x²+4-4x)=3a(x+2)²(x-2)²
9、12ab^2(y-x)+9b^3(x-y)+4a^2b(x-y)=b(x-y)(9b²-12ab+4a²）=b(x-y)(3b-2a)²
10、4a²b²-(a²+b²)²=(2ab+a²+b²)(2ab-a²-b²)=-(a+b)²(a-b)²
11、(x+2y)³-(x+2y)=(x+2y)[(x+2y)²-1]=(x+2y)(x+2y+1)(x+2y-1)
12、x^2(2x-5)+4(5-2x)=(2x-5)(x²-4)=(2x-5)(x+2)(x-2)
13、4a(x+3y)²+12a(x+3y)+9a=a[4(x+3y)²+12（x+3y）+9]=a[2(x+3y)+3]²
14、同第8题