Answer
See below
Work Step by Step
From geometry, a line tangent to a circle is perpendicular to the radius at the point of tangency. The radius with endpoint $(2,-3)$ has slope $m=\frac{0+3}{0-2}=-\frac{3}{2}$, so the slope of the tangent line at $(2, -3)$ is the negative reciprocal of $\frac{2}{3}$. An equation of the tangent line is as follows:
$$y+3=\frac{2}{3}(x-2)\\y=\frac{2}{3}x-\frac{13}{3}$$
