Internal rate of return

Generally, the internal rate of return is a measurement of return expressed as a percentage. It’s furthermore found by solving a hypothetical NPV calc: What rate of return sets cash outflows and incomes equal? The interest rate therefore serves as a discounting pivot point.
In finance, its a basic and straightforward question. But the actual calculation is problematic. At least, if we are looking at it from a closed-form algebraic solution form.

The reason for this difficulty is due to the fact that multiple cashflow discounting periods will lead to the so-called order of the solution polynomial having values far exceeding the quintic solution.

If this preamble seems confusing, I would recommend watching the following introductory video first.