Determination numerele care lipsesc din spatiile punctuate
a. 5,15,25,. ,. ,. B. 7,14,21,. ,. ,. C. 15,30,90,. ,. ,. D. 122,3124,5206,. ,. ,. E. 122,3412,4520,. ,. ,. F. 3,4,12,48,. ,. ,. .