Answer:
Given functions,


Since, by the compositions of functions,
1. (g◦f)(x) = g(f(x))


Since, (g◦f) is defined,
If 3 - x² ≥ 0
⇒ 3 ≥ x²
⇒ -√3 ≤ x ≤ √3
Thus, Domain = [-√3, √3]
2. (f◦g)(x) = f(g(x))


Since, (g◦f) is defined,
If x ≥ 0
Thus, Domain = [0, ∞)
3. (f◦f)(x) = f(f(x))




Since, (f◦f) is a polynomial,
We know that,
A polynomial is defined for all real value of x,
Thus, Domain = (-∞, ∞)
ANSWER

EXPLANATION
The sum of an arithmetic sequence whose first term and last terms are known is calculated using

From the given information, the first term of the series is

and the last term of the series is

The sum of the first 26 terms is



Answer: 9 * (5 - y)
Explanation:
Times: multiplication
Difference: subtraction
y: the unknown variable