Răspuns:
Explicație pas cu pas:
2x-3 divide 9 pt ca expresia sa fie numar intreg
2x-3∈D9
D9={-1,-3,-9, 1,3,9}
2x-3=-1, x=1∈Z
2x-3=-3, x=0∈Z
2x-3=-9, x=-3∈Z
2x-3=1, x=2∈Z
2x-3=3, x=3∈Z
2x-3=9, x=6∈Z
A={-3,0,1,2,3,6}
b. 2x+1∈D7
D7={-7, -1,1,7}
2x+1=-7, x=-4∈Z
2x+1=-1, x=-1∈Z
2x+1=1, x=0∈Z
2x+1=7, x=3∈Z
B={-4,-1,0,3}