Answer:
The first one = add three matches to the right side(on horizontal, two that or on top and bottom vertically.)
Second: Start with 5, and keep adding 3 until 26. 5 + 3+3+3+3+3+3+3
Or (26-5)/3 = 21/3 = 7
7 additions are needed so 7+1 = 8
Third: I believe you can answer this with this info
Explanation: