So, I got a few problems in my work like this:

V+3          v-4
____    _____
v^2-16 , V^2-9v+20

the directions say "Find equivalent expressions that have the least common denominator"

The example when solved, looks like this:

(v+3)(v+5)
_________
(v+4)(v-4)(v+5)

then it has me do the same with the second problem, which ends up looking like this:
(v-4)(v-4)
________
(v+4)(v-4)(v+5)

I want to figure out how to calculate these kinds of problems in Wolfram|Alpha, I've tried just about everything. I can't even search the internet for how to solve these, as I don't even know what kind of problems these are classified as.