Find .
Is that what you are looking for?
I only simplified the brackets and replace an 'x' by 'times', and simplified the denominator a little and added dx.
As you can see, the denominator and numerator can be further simplified.
Can you continue now?
EDIT: Since the 'x' is an actual x, this becomes:
Actually, the limits flip, but the overall sign does NOT change. That's because you get one minus sign for the differential, and one minus sign for the lone x in the numerator. So you get
Now, what happens when you flip the right integral's limits back to what they are on the LHS?
No, no. What usually happens when you flip limits? (Scroll down the link to just below the Conventions section).