The correct equation that shows the relation between the vertices of a dilated figure and the vertices of the original figure when the original figure is dilated using a scale factor of 5 is:
\[ (x_2, y_2) = (5x_1, 5y_1) \]
This means that each vertex of the original figure \((x_1, y_1)\) is multiplied by the scale factor (5 in this case) to obtain the corresponding vertex of the dilated figure \((x_2, y_2)\).