Question 115886
The domain is the value of the argument of the function where the function makes sense. 
1. For the log function, the argument must always be greater than zero.
{{{(t-5)>0}}}
{{{t>5}}} is the domain.
2. There are no restrictions, the domain for x is ({{{-infinity}}},{{{infinity}}}).
3. Just like the log function, the ln function requires the argument to be greater than zero.
{{{(t+4)>0}}}
{{{t>-4}}} is the domain. 
4. There are no restrictions, the domain for t is ({{{-infinity}}},{{{infinity}}}).