To find f - g, we need to subtract g(x) from f(x) for all values of x.
f(x) = 3x + 6
g(x) = 6x + 3
f(x) - g(x) = (3x + 6) - (6x + 3)
Simplifying the right-hand side by distributing the negative sign:
f(x) - g(x) = 3x + 6 - 6x - 3
Combining like terms:
f(x) - g(x) = -3x + 3
Therefore, f - g is equal to -3x + 3.