hmmmm first off, what is x -2? it doesn't say above, but we can safely assume is a factor of the Area, and therefore, since it's a rectangle, is a dimension, either the length or width.
since we know the Area of the rectangle is 4x² - 13x +10, and we know one of the dimensions is x-2, then the quotient of dividing the area by that dimension, will simply give the other dimension. Recall that the Area of a rectangle is just the product of length * width.

thus, that's the other factor of the Area, and therefore, the other dimension.