Any number raised to the power 0 is 1.
This follow from the law of multiplications of power:
xa * xb = xa+b
Now, if you put b = 0, you get xa + x0 = xa+0
and since a+0 = a, the right hand side is xa.
So you have xa * x0 = xa
and using the property of the multiplicative identity, xa =
1.