Question 977079
(x-2)/(2a-3)  * (3-2a)/2(x-2)  I factored the denominator of the second part.

recognize that 3-2a = -(2a-3), so I may rewrite.

(x-2)/(2a-3) * - (2a-3)/(2(x-2))

 -   1/2    Everything else cancels out, the (x-2) in the first term with 2(x-2) below in the second, leaving a 2, and the (2a-3) cancels.  

Key thing
(4-x) does not cancel (x-4) as an example.
BUT  4-x= - (x-4) and then you cancel.  You have to have a sign change.