(2*(-21)+3*(20-1))*20/2 = 150
ответ:150
-21,-18,-15,-12,-9,-6,-3,0,3,6,9,12,15,18,21,24,27,30,33,36
24+27+30+33+36=150
(2*(-21)+3*(20-1))*20/2 = 150
ответ:150
-21,-18,-15,-12,-9,-6,-3,0,3,6,9,12,15,18,21,24,27,30,33,36
24+27+30+33+36=150