Given function :
For check the g(x) is a invers of f(x) the any value of x the f(x) output use as g(x) input then value of output of g(x) is equal to "x"
for g(x)
so g(x) is a invers of f(x) .
The property show that convert any function to invers function then value of input convert in output and value of output convert in input that mean x change as y and change as x and above method full fill the condition.