The unshaded trapezoid is the image of the shaded trapezoid after a series of transformations.

On a coordinate plane, a shaded trapezoid has points (negative 5, 1), (negative 4, 5), (negative 3, 5), (negative 2, 1). An unshaded trapezoid has points (0, 1), (1.5, 9), (4.5, 9), (6, 1).

What is the value of x?
3
9
12
18