Solution:
The vertex equation of an ellipse is;
[tex]\frac{(x-h)^2}{a^2}+\frac{(y-k)^2}{b^2}=1[/tex]Thus, given the center;
[tex](h,k)=(-2,3)[/tex]Then, the equation whose graph is an ellipse centered at (-2,3) is;
[tex]\frac{(x+2)^2}{12}+\frac{(y-3)^2}{18}=1[/tex]