Question

How can I factor t^2-12t+27

Answer 1

The factors of 27 that add up to 12 are in the list: 1,27 or 3,9.  Only 3,9 works,
so (x-3)(x-9) are the factors.

Answer 2

T^2-12t+27
T^2-9t-3t+27
T(t-9)-3(t-9)
(t-9)(t-3)