-36 , 18 , -9
b₁= -36 b₂= 18
S∞ = b₁/(1-q) = -36
b₂=1*q
q= b₂/b₁ =18/-36 = - 1/2
S∞= -36/1-(-1/2) = -36/1+1/2 = -36:3/2 = -36 * 2/3 = -12*2= -24
-36 , 18 , -9
b₁= -36 b₂= 18
S∞ = b₁/(1-q) = -36
b₂=1*q
q= b₂/b₁ =18/-36 = - 1/2
S∞= -36/1-(-1/2) = -36/1+1/2 = -36:3/2 = -36 * 2/3 = -12*2= -24
ответ: S∞= -24