Find the value of x so the rectangles have the same area

Area of rectangles = width * length.
So x*12 = 12x = area of first rectangle
So 16*(x-2) = 16x -32 = area of second rectangle

The question states to make them equal, so:
first rectangle = second rectangle
12x = 16x -32
Solve for x
-4x = -32
4x = 32
x = 8