Find the absolute maximum value and the absolute minimum value, if any, of the function.
g(t)=t/t-2 on[4,6]
I assume you meant
g(t) = t/(t-2)
g' (t) = ( (t-2)(1) - t(1) )/(t-2)^2
= -2/(t-2)^2
let -2/(-2)^2 = 0 for a max/min
this has no solution,
so the max and mins must occur at the endpoints of your domain
g(4) = 4/(4-2) = 2
g(6) = 6/(6-2) = 6/4 = 3/2
so the max value is 2 and the minimum value is 3/2