Function f is defined at all points of the real line.
When x < – 1, we have f(x) = – 2; which is constant and so it is continuous.
∴ f is continuous at x = – 1
In the interval –1 < x < 1, we have f(x) = 2 x, which being a linear polynomial, is continuous.
∴ f is continuous at x = 1
When x > 1, we have f (x) = 2. which is constant and so it is continuous.