You have a custom operation ^ and the following equation x ^ y = 2x + y, Now what is the value of a in 2 ^ a = a ^ 3 BTW I also don't know the answer and is a question of some paper.

x^y = 2x +y 2^a = a^3 ======================= 2^a = 2(2)+a 2^a = 4+a ================= a^3 = 2(a)+3 =============== 4+a = 2a+3 2a-a=4-3 a=1