As per given by the solution,
There are given that the equation,

Now,
According to the question, find the value of t(s(-4)).
Then,
First find the value of s(-4);
So,
The given equation is ,

Put the value of x =-4 into above equation,
Then,

Now,
For finding the value of t(s(-4)):
From the second equation,

In above equation, put the value of s(-4) instead of x.
So,

Hence, the value of t(s(-4)) is -74.