Ребята,срочно помогите.

1.Раскройте скобки:

1)a+(b-c+d)

2)a-(b-c-d)

3)a-(b+c+d)

4)a+(b+c-d)

5)(a-b)+(c-d)

6)(x+y)-(z+t)

7)(m-n)-(k-t)

8)(t+s)+(-p-m)

Заранее спасибо:)

Очень срочно!!!

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