index laws

125 ^ (-4/3)

Note that we can write this as

( 125^1/3)^(-4)        the value in the first parentheses is just the cube root of 125  = 5

So we have

(5)^(-4)          {    remember that  a^(-m)  =   1 / a^m  }

1 / 5^4   =    1 / (5^2 * 5^2)  =   1 / (25 * 25)   =  1 / 625