Answer
$f(c)=\displaystyle\lim_{x\rightarrow c} f(x)$
Work Step by Step
A function $f(x)$ has a removable discontinuity if $\displaystyle\lim_{x\rightarrow c} f(x)$ exists, but $\displaystyle\lim_{x\rightarrow c} f(x)\not=f(c)$.
The function can be redefined in order to be continuous in $x=c$ in only one way by assigning:
$f(c)=\displaystyle\lim_{x\rightarrow c} f(x)$
