Question

ex. 4 va rog multttt e urgent!!!!!!!!​

Answer 1

A∩B=?

15:(3x+1) ∈ Z → 3x + 1 ∈ $D_{15}$

3x + 1 ∈ {-15, -5, -3, -1, 1, 3, 5, 15}/-1

3x ∈ {-16, -6, -4, -2, 0, 2, 4, 14}/ :3

x ∈ {-16/3, -2, -4/3, -2/3, 0, 2/3, 4/3, 14/3}

A ={-5,(3); -2; -1,(3); -0,(6); 1,(4); 4,(6)}

-5<x-1$\leq$3 /+1

-4<x$\leq$4

B = {-3, -2, -1, 0, 1, 2, 3, 4}

A∩B∈{-2}