x*(x-1)/2=55
(x²-x)/2=55
0.5x²-0.5x=55
0.5x²-0.5x-55=0
D=(-0.5)²-4*0.5*2*0.5=110.25
x1=(√110.25-(-0.5))/(2*0.5)=11
x2=(-(√110.25)-(-0.5))/(2*0.5)=-10
ответ: 11 команд
x*(x-1)/2=55
(x²-x)/2=55
0.5x²-0.5x=55
0.5x²-0.5x-55=0
D=(-0.5)²-4*0.5*2*0.5=110.25
x1=(√110.25-(-0.5))/(2*0.5)=11
x2=(-(√110.25)-(-0.5))/(2*0.5)=-10
ответ: 11 команд