Answer:
(a) Find (f + g)(x)
To find (f + g)(x), we add the two functions f(x) and g(x):
(f + g)(x) = f(x) + g(x) = (4x + 9) + (9x - 5) = 13x + 4
The domain of (f + g)(x) is all real numbers, since there are no restrictions on x that would make (f + g)(x) undefined.
(b) Find (f - g)(x)
To find (f - g)(x), we subtract the function g(x) from f(x):
(f - g)(x) = f(x) - g(x) = (4x + 9) - (9x - 5) = -5x + 14
The domain of (f - g)(x) is all real numbers, since there are no restrictions on x that would make (f - g)(x) undefined.
(c) Find (f * g)(x)
To find (f * g)(x), we multiply the two functions f(x) and g(x):
(f * g)(x) = f(x) * g(x) = (4x + 9)(9x - 5) = 36x^2 + 11x - 45
The domain of (f * g)(x) is all real numbers, since there are no restrictions on x that would make (f * g)(x) undefined.
(d) Find (f / g)(x)
To find (f / g)(x), we divide the function f(x) by g(x):
(f / g)(x) = f(x) / g(x) = (4x + 9) / (9x - 5)
The domain of (f / g)(x) is all real numbers except x = 5/9, since this value would make the denominator of (f / g)(x) equal to zero, resulting in division by zero, which is undefined.
(e) Find f(g(x))
To find f(g(x)), we substitute g(x) into the expression for f(x):
f(g(x)) = 4g(x) + 9
Substituting the expression for g(x), we get:
f(g(x)) = 4(9x - 5) + 9 = 36x - 11
The domain of f(g(x)) is all real numbers, since there are no restrictions on x that would make f(g(x)) undefined.
(f) Find g(f(x))
To find g(f(x)), we substitute f(x) into the expression for g(x):
g(f(x)) = 9f(x) - 5
Substituting the expression for f(x), we get:
g(f(x)) = 9(4x + 9) - 5 = 36x + 76
The domain of g(f(x)) is all real numbers, since there are no restrictions on x that would make g(f(x)) undefined.
(g) Find f(f(x))
To find f(f(x)), we substitute f(x) into the expression for f(x):
f(f(x)) = 4f(x) + 9
Substituting the expression for f(x), we get:
f(f(x)) = 4(4x + 9) + 9 = 16x + 45
The domain of f(f(x)) is all real numbers, since there are no restrictions on x that would make f(f(x)) undefined.
(h) Find g(g(x))
To find g(g(x)), we substitute g(x) into the expression for g(x):
g(g(x)) = 9
Explanation: