1. (а - b) + (c - d) = a - b + c - d
2. -(-a + b) -(-c - d) = + a - b + c + d
3. (a + b) - (c + d) = a + b - c - d
4. -(a + b) + (-c - d) = - a - b - c - d
5. -(a - b) - (c + d) = - a + b - c - d
1. (a - b) - (c - d) = a - b - c + d
2. -(-a - b) + (-c - d) = + a + b - c - d
3. (a + b) + (-c + d) = a + b - c + d
4. -(a - b) + (c - d) = - a + b + c - d
5. -(a + b) - (c + d) = - a - b - c - d