The midpoint of $(5,0)$ and $(4,3)$ is
\[\left( \frac{5 + 4}{2}, \frac{0 + 3}{2} \right) = \left( \frac{9}{2}, \frac{3}{2} \right).\]This tells us that the vector being reflected over is a scalar multiple of $\begin{pmatrix} \frac{9}{2} \\ \frac{3}{2} \end{pmatrix}.$  We can then assume that the vector being reflected over is $\begin{pmatrix} 3 \\ 1 \end{pmatrix}.$

[asy]
usepackage("amsmath");

unitsize(1 cm);

pair A, B, M, O, R, S;

O = (0,0);
A = (5,0);
R = (4,3);
B = (-2,3);
S = (1/5,-18/5);
M = (A + R)/2;

draw((-3,-1)--(5,5/3),red + dashed);
draw(O--M,red,Arrow(6));
draw((-4,0)--(6,0));
draw((0,-4)--(0,4));
draw(O--A,Arrow(6));
draw(O--R,Arrow(6));
draw(A--R,dashed,Arrow(6));
draw(O--B,Arrow(6));
draw(O--S,Arrow(6));
draw(B--S,dashed,Arrow(6));
label("$\begin{pmatrix} 5 \\ 0 \end{pmatrix}$", A, S);
label("$\begin{pmatrix} 4 \\ 3 \end{pmatrix}$", R, NE);
label("$\begin{pmatrix} -2 \\ 3 \end{pmatrix}$", B, NW);
label("$\begin{pmatrix} \frac{9}{2} \\ \frac{3}{2} \end{pmatrix}$", M, N);
[/asy]

The projection of $\begin{pmatrix} -2 \\ 3 \end{pmatrix}$ onto $\begin{pmatrix} 3 \\ 1 \end{pmatrix}$ is
\[\operatorname{proj}_{\begin{pmatrix} 3 \\ 1 \end{pmatrix}} \begin{pmatrix} -2 \\ 3 \end{pmatrix} = \frac{\begin{pmatrix} -2 \\ 3 \end{pmatrix} \cdot \begin{pmatrix} 3 \\ 1 \end{pmatrix}}{\begin{pmatrix} 3 \\ 1 \end{pmatrix} \cdot \begin{pmatrix} 3 \\ 1 \end{pmatrix}} \begin{pmatrix} 3 \\ 1 \end{pmatrix} = \frac{-3}{10} \begin{pmatrix} 3 \\ 1 \end{pmatrix} = \begin{pmatrix} -\frac{9}{10} \\ -\frac{3}{10} \end{pmatrix}.\]Hence, the reflection of $\begin{pmatrix} -2 \\ 3 \end{pmatrix}$ is $2 \begin{pmatrix} -\frac{9}{10} \\ -\frac{3}{10} \end{pmatrix} - \begin{pmatrix} -2 \\ 3 \end{pmatrix} = \boxed{\begin{pmatrix} 1/5 \\ -18/5 \end{pmatrix}}.$
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
A reflection takes $\begin{pmatrix} 5 \\ 0 \end{pmatrix}$ to $\begin{pmatrix} 4 \\ 3 \end{pmatrix}.$  Which vector does the reflection take $\begin{pmatrix} -2 \\ 3 \end{pmatrix}$ to?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
\begin{pmatrix} 1/5 \\ -18/5 \end{pmatrix}
A reflection takes $\begin{pmatrix} 5 \\ 0 \end{pmatrix}$ to $\begin{pmatrix} 4 \\ 3 \end{pmatrix}.$  Which vector does the reflection take $\begin{pmatrix} -2 \\ 3 \end{pmatrix}$ to?
test