(t-1)^2=2t^2-t-29 . multiply out the left side
t^2 - 2t + 1 = 2t^2-t-29 . move everything to the right
0 = t^2 + t - 30 . factor
0 = (t - 5)(t + 6) . set each factor = to 0 and solve
try expanding the (t-1)^2 and then bringing all that to the opposite side of the equation and solving algebraically (i.e. add the t^2 terms, the t terms and the constant terms). The equation will have to equal zero but if a t^2 exists then it is a polynomial and thus has 2 answers.
(t-1)^2 = t^2 -2t +1
so you have t^2-2t+1=2t^2-t-29
subtract t^2 from both side you get
-2t+1=t^2-t-29
add 2t to each side
you get 1= t^2+t-29
0=t^2+t-30
(t+6)(t-5)
t=-6 or t= +5