x- - 9x + 20 4. Given y = f(x) = X - 4 (a) Is it possible to apply the quotient limit theorem to find the limit of this function as x - 4? (b) is this function continuous at x = 4? Why? (c) Find a function which, for x # 4, is equivalent to the given function, and obtain from the equivalent function the limit of y as x - 4