Question

A={x apartine Z/ 6 supra 2x+1 apartine Z}
B={x apartine Z/ (2x+rad 3)(2-xrad 3)=1}
 Aflati elementul comun multimilor A si B.
  A+B=?

Answer 1

2x+1∈D6 (multimea divizorilor lui 6)
D6={+-1,+-2,+-3,+-6}
2x+1=-1⇒2x=-2,x=-1
2x+1=1⇒x=0
2x+1=2⇒x=1/2∉Z
2x+1=-2⇒x=-3/2∈Z
2x+1=3⇒x=1
2x+1=-3⇒x=-2
A={-2,-1,0,1}

2x+√3=2x-√3
√3=-√3
x∈Ф
B=Ф
A+B={-2,-1,0,1}