c) C = (2^5. 5^5 - 10^6)/ 3. 5^5 ;

c) $C=\frac{2^5{.5}^5-{10}^6}{{3.5}^5}=\frac{{\left(2.5\right)}^5-{10}^1{.10}^5}{{3.5}^5}=\frac{{10}^5-{10.10}^5}{{3.5}^5}$.

$=\frac{{10}^5.\left(1-10\right)}{{3.5}^5}=\frac{{10}^5.\left(-9\right)}{{3.5}^5}=\frac{-9}{3}.{\left(\frac{10}{5}\right)}^5=-{3.2}^5=-3.32=-96$.