Find the value of x where the function is discontinuous.
f(x)=x^3+3^x

A(x)=x^3 is a polynomial function, and polynomial functions are continuous for all x, 

b(x)=3^x is an exponential function, continuous for all x.

f(x)=a(x)+b(x) is continuous because the sum of 2 continuous functions is a continuous function.

f is continuous for all x in the real numbers

Igot the answer of 15.8 years.