Răspuns:
Explicație pas cu pas:
Un numar este divizibil cu trei daca si numai daca suma cifrelor numarului este divizibila cu 3.
ASA CA AVEM:
a) 12x=120,123,126,129
b)5xy=501,504,507,510,513,516,519,522,525,528,531,534,537,540,543,546,549,552,555,558,561,564,567,570,573,576,579,582,585,588,591,594,597
c)7xy, x este impar => x=3,9
=>7xy=732,735,738,792,795,798
d)2x5y=2052,2055,2058,2151,2154,2157,2250,2253,2256,2259,2352,2355,2358,2451,2454,2457,2550,2553,2556,2669,2652,2655,2658,2751,2754,2757,2850,2853,2856,2859,2952,2955,2958
