Question

I don’t understand my check of solution for the equation ^4√x+12=15 with x=81 and how it becomes 15 if √81 is 9

Answer 1

your first step would be to simplify the radical by breaking the radicand up into a product of known factors, assuming positive real numbers.
^4√81=3
how you do this is basically its saying is what number do you have to multiple to itself 4 times in order to get 81. which is 3
then 3+12=15, so 15=15 that meaning this statement is true :D