We know that if two functions f(x) and g(x) are continuous then {f(x) +g(x)},{f(x)-g(x)}, {f(x).g(x)} and are continuous.

Since, f(x) = 2x and are polynomial functions, they are continuous everywhere.

⇒ {f(x) +g(x)},{f(x)-g(x)}, {f(x).g(x)} are continuous functions.

for,

now, f(x) = 0

⇒ 4x = 0

⇒ x = 0

∴ is discontinuous at x=0.