问几道关于公式法的初二数学题

分解因式：

1. -1/25m²+16

2. 16（x-1）²-（x+2）²

3. a²-（b+c）²

4. a²+ax-b²+bx

5. (a-b)(a²-ab+b²)-ab(a-b)

6. (x+y)²+4(x-y)²-4(x²-y²)

1. -1/25m²+16=(4-1/5m)*(4+1/5m)

2. 16（x-1）²-（x+2）²=[4(x-1)-(x+2)]*[4(x-1)+(x+2)]=(3x-6)*(5x-2)

3. a²-（b+c）²=(a-b-c)*(a+b+c)

4. a²+ax-b²+bx=(a-b)*(a+b)+(a+b)*x=(a+b)*(a-b+x)

5. (a-b)(a²-ab+b²)-ab(a-b)=(a-b)*(a²-ab+b²-ab)=(a-b)^3

6. (x+y)²+4(x-y)²-4(x²-y²)=(x+y)²+4(x-y)²-4(x-y)*(x+y)=[(x+y)-2(x-y)]²=(3y-x)²

1.(4+1/5m)(4-1/5m)

2.(5x-2)(3x-3)

1 (4-1/5m)*(4+1/5m)

2 (3x-6)*(5x-2)

3 (a-b-c)*(a+b+c)