Answer
a) -125
b) -125
c) 4
Work Step by Step
Note that parenthesis matter:
a) $(-5^{3})$ = (-5) $\times$ (-5) $\times$ (-5) = -125
b) $-5^{3}$ = - ($5^{3}$) = -(125) = -125
c) $(-5^{2})$ $\times$ ($\frac{2}{5}$)$^{2}$= 25 $\times$ $\frac{4}{25}$ = 4