Question

A {X €Z|3X+2 supra x-1€Z} vezi daca 6€A si determinați multi a A

Answer 1

x-1/3x+2⇒ x-1/3x+2
x-1/x-1 ⇒x-1/3x-3 (-) ⇒ x-1/5⇒ x-1∈ {1,-1,5,-5}⇒ x∈ { 2,0,6,-4}
6∈A si A = {-4,0,2,6}