Разложите на множители

1) (x-y) + b (y-x)

2) 2b (x-y) - (y-x)

3) a (b-c) + x (b-c) - 7 (b-c)

4) x (a-2) + y (2-a) - (2-a)

5) 3 (x+y) (x-y) - (x+y) ^2

6) 3m (n-m) ^2-9m^2 (m-n)

1) (x-y) + b (y-x) = - (y-x) + b (y-x) = (y-x) (b-1)

2) 2b (x-y) - (y-x) = 2b (x-y) + (x-y) = (x-y) (2b+1)

3) a (b-c) + x (b-c) - 7 (b-c) = (b-c) (a+x-7)

4) x (a-2) + y (2-a) - (2-a) = x (a-2) - y (a-2) + (a-2) = (a-2) (x-y+1)

5) 3 (x+y) (x-y) - (x+y) ² = (x+y) (3 (x-y) - (x+y)) = (x+y) (3x-3y - x-y) = 2 (x+y) (x-y)

6) 3m (n-m) ² - 9m ² (m-n) = (m-n) (3m (n-m) - 9m ²) = (m-n) (3mn-3m ² - 9m ²) = 3m (m-n) (n-4m)