Answer the following questions related to radicals and fractional exponents:
a. (a) State the meaning of the fractional exponent anm for a>0 and natural numbers m,n.
b. (b) Explain, with reasons, whether the value of a fraction changes when both its numerator and denominator are multiplied by the same non–zero expression.
c. (c) Using the explanation in part (b), describe why the operation known as "rationalising the denominator" is mathematically valid.