>>/797846/
> t^2-t^3=12

-t^3+t^2-12=0

t^3-t^2+12=0

t^3-t^2+12=(t+2)(t^2-3*t+6)=0

|t+2=0, => t=-2;
|t^2-3*t+6=0

D=(-3)^2-4*1*6=-15

t=(3±(-15)^(1/2))/2=(3±i*15^(1/2))/2
——————————————————-
t=-2, t=(3±i*15^(1/2))/2