From the two foci definition of a hyperbola: For foci $f_{1}$ and $f_{2},$ a hyperbola is the set of all points $(x, y)$ where the difference of the distances from $f_{1}$ to $(x, y)$ and $f_{2}$ to $(x, y)$ is constant. Verify the points (2,3) and $(-3,-2 \sqrt{6})$ are on the graph of the hyperbola from Exercise $33 .$ Then verify $d_{1}-d_{2}=d_{3}-d_{4}$ (GRAPH CAN'T COPY)