Simplify 125 ^ -2/3

= (1/125) ^ 2/3  = (1/5) ^ 2 = 1/25 To find a number to a negative power, you invert it (flip it so that 125 becomes 1/125) To find (1/125) ^ 2/3, find the cube root of 1/125 (=1/5) and then square it (=1/25)