Tolng ya sama prosesnya juga...

f(t) = 0
t^12 - 1 = 0
(t^6 + 1)(t^6 - 1) = 0
(t^6 + 1)(t^3 + 1)(t^3 - 1) = 0
1) t^6 + 1 = 0 => t^6 = -1 => tidak ada nilai t real yg memenuhi
2) t^3 + 1 = 0 => t^3 = -1 => t = -1
3) t^3 - 1 = 0 => t^3 = 1 => t = 1
Jadi banyaknya akar real dari f(t) = 0 ada 2 yaitu (t = 1 dan t = -1)