We have G=(1,2) and x@y=(3xy-4x-4y+6)/(2xy-3x-3y+5) .How you find uin G such that x@u=x?

1 Answer
Apr 28, 2017

u = 3/2

Explanation:

Solving x @ u = x we have

(3 x u - 4 x - 4 u + 6)/(2 x u - 3 x - 3 u + 5) = x

or

3 x u - 4 x - 4 u + 6 - x (2 x u - 3 x - 3 u + 5)=0

or

6 - 4 u - 9 x + 6 u x + 3 x^2 - 2 u x^2=0

or

(6-4u)+(6u-9)x+(3-2u)x^2=0

this relationship must be true for all x so

{(6-4u=0),(6u-9=0),(3-2u=0):}

and solving for u we have

u = 3/2