Answer:
-439
Step-by-step explanation:
(s circle t) (negative 7) is a notation for a compound function.
A compound function is a function that has as an argument another function.
Another notation for this compound function is s(t(-7)), that is, the result of the function t(-7) is the value that will be used in the function s(x).
So, first we calculate the value of t(-7):
t(x) = 3x
t(-7) = 3*(-7) = -21
Now, we apply this value for s(x):
s(x) = 2 - x2
s(t(-7)) = s(-21) = 2 - (-21)^2 = 2 - 441 = -439
