多項式的因式分解

All answers start from the 2nd step

No. one a, =4(3x-4)
No. one b, =5(2a+3b)
No. two a, =2(3a+2b-4)
No. two b, =x(x²-x+2)
No. three a, =3x(2x+3)
No. three b, =3ab(5ab²-7b²+2a)
No. four a, =(a+b)[3a-(a-b)] = (a+b)(2a+b)
No. four b, =(2m+n)(4m-n+7n-m) = (2m+n)(3m+6n) = (3(2m+n)(m+2n)
No. five a, =(2a+b)(x-y)+b(x-y) = (x-y)(2a+b+b) = 2(x-y)(a+b)
No. six a, =2x(a-b)-3y(a-b) = (a-b)(2x-3y)
No. six b, =8x²(x-1)+4(x-1) = 4(x-1)(2x²+1)
No. seven a, =a(abc-1)+b(abc-1)-c(abc-1) = (abc-1)(a+b-c)
No. seven b, =2a(x-2y)-4b(x-2y)+6c(x-2y) = 2(x-2y)(a-2b+3c)

No. eight, = 4xy²(2x²-5x+1) = 4(3)(-1) = -12
No. nine, = 2xy(3x-x²-1) = -2xy(x²-3x+1) = -2(7)(2) = -28
No. ten a, =1+n+m+mn = (1+n)+m(1+n) = (1+n)(1+m)
No. ten b, =1+p+n+np+m+mp+mn+mnp = (1+p)+n(1+p)+m(1+p)+mn(1+p)
= (1+p)(1+n+m+mn) = (1+p)(1+n)(1+m)
No. eleven a, =a²+3a+2
No. eleven b, =x^4+6x^3+9x²+x²+3x+2 = x^4+6x^3+10x²+3x+2
No. twelve a, =2x²+3x-2
No. twelve b, = (x+2)(2x-1)(x+1)=(2x²+3x-2)(x-1) =2x^3+x²-5x+2
No. twelve c, = (2x^3+x²-5x+2)+(6x²+9x-6) = (x+2)(2x²+x-1)+3(2x²+3x-2)
= (x+2)(2x-1)(x+1)+3(x+2)(2x-1) =(x+2)(2x-1)(x+4)
No. twelve d,
2736:
1x2736
2x1368
3x912
4x684
6x456
8x342
9x304
12x228
16x171
18x152
19x144
24x114
36x76
38x72
48x57

ans= 1,2,3,19,57
No. thirteen a, = 2x²-x-1
No. thirteen b, = x(2x²-x-1) = 2x^3-x²-x
No. thirteen c, = 2x^3-x²-x-2x²+x+1 = x(2x²-x-1)-(2x²-x-1) = (x-1)(2x²-x-1)
= (x-1)(x-1)(2x+1) = (x-1)²(2x+1)