Answer
$(1,4).$
Work Step by Step
We know that the centre is the midpoint of the two foci.
The midpoint $M$ of the line segment from $P_1(x_1,y_1)$ to $P_2(x_2,y_2)$ is: $(\frac{x_1+x_2}{2},\frac{y_1+y_2}{2})$.
Hence here: $C=\left(\frac{-4+6}{2},\frac{4+4}{2}\right)=\left(\frac{2}{2},\frac{8}{2}\right)=(1,4).$
