Step-by-step:
The first flip numbers will always add up to 1 so you do
1 - 2/7= 5/7
now it gets easy...
The second flip head will be 2/7 because it is a biased dice and the second flip tail will be 5/7
This also applies for the bottom 2: 2/7 head, 5/7 tails
hope this helped :)