Given as
f: R → R ∈ f(x) = x2 and g : R → R ∈ g(x) = x2
f is the defined from R to R, the domain of f = R.
g is the defined from C to C, the domain of g = C.
The two functions are equal only when the domain and co-domain of both the functions are equal.
In this case, the domain of f ≠ domain of g.
Thus, f and g are not equal functions.