Разложите на множители:

1. b^2-c^2-b+c

2. a+b-a^2+b^2

3. a^2-a-c^2+c

4. m-m^2-n+n^2

1) (b^2-c^2) - (b-c) = (b-c) (b+c) - (b-c) = (b-c) (b+c-1)

2) (b^2-a^2) + (b+a) = (b-a) (b+a) + (b+a) = (b+a) (b-a+1)

3) (a^2-c^2) - (a-c) = (a-c) (a+c) - (a-c) = (a-c) (a+c-1)

4) (n^2-m^2) - (n-m) = (n-m) (n+m) - (n-m) = (n-m) (n+m-1)