do you mean like this:

Question

720/(V-30) + 720/(V+30) = 10

Get a common denominator of
(v-30)(v+30)
then multiplying both sides by that, then
(v-30)(v+30)X 720(V+30) + (v-30)(v+30) X 720(V-30)=(v-30)(v+30)X 10(v-30)(v+30)

then multily out, and solve for v.
720(v-30)+720(v+30)=10
720v-21600+720v+21600=10
1440v=10
v=144

The right side: you have to multipy both sides by (v-30)(v+30
720(v-30)+720(v+30)=10(v-30)(v+30)
You will get a quadratic.

As an aside, 1440v if it equalled 10, does not give v=144. It gives 1/144.