題組內容

6. Let (ZxZ,⊕) be the group with (a, b)⊕(c, d) = (atc+2, 6+d-2) for any (a, b), (c, d) ∈ ZxZ where a+c+2 and b+d-2 are computed using ordinary addition and subtraction in Z.

(a)3(4,5)=(4,5)⊕(4,5)⊕(4,5)=?