Answer: have strong evidence and so people don't think that it is their own biased opinion. plus you can cite things if you have a good source hope this helps:D
You plug them into each other for x like so: (3(radical sign)-4)^3+4 -4+4 You're left with x Then do the same for the other one 3(radical sign)(x^3+4)-4 X+4-4 Left with x again there fore it is an inverse