Refer to the diagram shown below.
The right vertex is at (14, -1), and the center is at (-1, -1).
Therefore the semi-major axis is
a = 14 - (-1) = 15
The right focus is at (8, -1).
Therefore
c = 8 - (-1) = 9.
The distance of the directrix from the center is
d = c²/a = 9²/15 = 81/15 = 27/5.
Therefore the equation for the left directrix is
x = -1 - 27/5 = -32/5
Answer: x = -27/5
