The denominator of the second fraction can be factored as (a-2)(2a-7), then it becomes doable. You cancel the (2a-7) factors, and are left with:
Do note that you have erased the fact that a≠0 and a≠7/2, so you should always mention that.
Do note that you have erased the fact that a≠0 and a≠7/2, so you should always mention that.