88 (1 combo)
66 (3 combos)
K8 (6 combos)
K6 (9 combos)
Q8 (4 combos)
Q6 (6 combos)
86 (6 combos)

There are total 35 combos. Since we split with 4 combos of Q8 we must count 2 of them we beat and 2 of them beats us... So there are 14 combos that we beat. Our equity is 14 / 35 = 40%.

Our equity in the pot is 40%;
We get 81,9 * 0,40 = 32,76 from the pot. Since we invest 25 for this income, our EV is 32,76 - 25 = 7,26.

Another way to calculate this;
We win 40% of the time... 56,9 * 0,40 = 22,76 (56,9 here is our profit. We must use the profit in this equation not the pot size.)
We lose 60% of the time... 25 * 0,60 = 15
Our EV is 22,76 - 15 = 7,26

Edit:
Sorry I missed that part. Equity needed here is 25 / 81,9 = ~0,305 = 30,5%