What is the zero of the liner function of f(x)= 3x+18?

Xy x xy if a and b are positive integers such that a*b=9 and b*a=72 what is the value of a/b

Whats is the value of the variables ?

For which of these functions is function composition commutative with ƒ(x) = (x + 1 /3x − 2) ? a - g(x) = (3x − 2/x + 1)b - g(x) = (3x − 3/x + 2)c - g(x) = (2x + 1/3x − 1)d - g(x) = (2x − 1/3x + 1)