a) $a=2^8=256$   `\ \ b=400\ \ \ \ \ a

b) $a={99}^2$

  `b=10000=100^2 \ \ \ a `b=10000=100^2 \ \ \ a

c) $a={\left(-11\right)}^5$

, `b = 100000=10^5 \ \ a

d) $a={19.5}^3$

  `b=8000=20^3 \ \ \ \ a

e) $a={\left(-30\right)}^3=-27000$

, `b= -25000 \ \ \ a

f) $a={0.4}^5<1$

,  $b=1a<1$

g) $a={0.03}^2=0,09$  , $b=0.001a>b$

h) $a={\left(-\frac{1}{2}\right)}^6>$     $b=0.01a>b$