Combine the numbers in each group using only addition, subtraction, division, exponentiation, factorials and brackets so that each triplet yields the same result (there might be several solutions):

**a. 2,7,8**

b. 2,5,26

c. 3,11,15

d. 3,49,71

Inspired by "e pluribus unum" 2003 & 2004.

b. 2,5,26

c. 3,11,15

d. 3,49,71