The power of (125 / 27) - 2 / 3 help

The power of (125 / 27) - 2 / 3 help

(125/27)^-2/3
1/(3√((125/27)^2))
=1/(25/9)
=9/25

Given that a, B and C are positive integers, a and B are prime numbers, the third power of a plus the C power of B plus a equals 2005, find the value of a + B + C?
Choose a.14 b.13 c.12 d.11 the answer is d.11 but I don't know why~~

Because of the third root in 2005, it is inferred that a is not greater than 12 (or it is definitely not greater than 12 from the alternative answers), which may be 11,7,5,3,2.11, B ^ C = 663, 7,7,7,5,5,19752, B ^ C = 1995. If B ^ C ends with 5, B ^ C is generally required to be 5, but

What is the negative power of 1 / 2
(1/2)-2

1 / 2 of the negative 2 power = (1 / 2 of the 2 power) 1 / 2 = (1 / 4) 1 / 4 = 4