Помогите решить несколько образцов!!! с - ( a + b )

C-a-b
-c+a-b
x-a+b+c-d
10-a+b-c-d
-8c+8
-1-5a-3b
5b-2a

C (a + b) = c a b;
c (a + b) = c + a  b;
x (a b) + (c d) = x a + b + c  d;
10 (a b) (c + d) = 10 a + b c d;
(8c 4) + 4 = 8c + 4 + 4 = 8c + 8 = 8  (1 c);
(5 4) (2 + 5a 3b) = 1 2 5a + 3b = 3b 5a 1;
5b (6b + a) (a 6b) = 5b 6b a a + 6b = 5b 2a