I am wondering. Since x is approaching zero, is the strategy and goal with solving rational polynomials to determine which direction x is approaching zero from? That is, from the left or the right?
Algebraically, I am having a problem understanding the attached photo. So, will point out what I don't understand in a step rather than what I think is going on.
Nonetheless, second step, first line. Where did the negative sign come from and why? Am I to assume the negative sign is due to x approaching negative infinity*? Still, I can not make the connection as to how the two are related.
Can someone care to explain?