t^2 - 8t = t(t-8)
Now, a cubic is not easy to factor, but since you're looking for a LCM, try dividing by (t-8).
No luck there. So, since the two polynomials have no common factors, the LCM is just
(t^3+8t^2+16)(t^2-8t)
Find the LCM
t^3+8t^2+16,t^2-8t
2 answers
Katie, shouldn't the 16 be negative? Check it out.