Use the given definition of continuity to prove f is continuos at 0.

Definition: For all £>0, there exists a k such that abs(f(x)-f(a))<£ for all x such at

abs(x-a)<k

F(x) = 1+x^2 when x>_0 , f(x)= 1-x^3 when x<0

I have trouble understanding the implications of the definition of continuity.

I have that abs(f(x)-f(0))=abs(f(x)-1) but don't what to do next.