a: \(\left(-\dfrac{1}{2}\right)^{30}=\left(\dfrac{1}{2}\right)^{30}\)
\(\left(-\dfrac{1}{8}\right)^{10}=\left(\dfrac{1}{8}\right)^{10}=\left(\dfrac{1}{2}\right)^{30}\)
Do đó: \(\left(-\dfrac{1}{2}\right)^{30}=\left(-\dfrac{1}{8}\right)^{10}\)
b: \(\left(\dfrac{81}{16}\right)^7=\left(\dfrac{3}{2}\right)^{28}< \left(\dfrac{3}{2}\right)^{30}\)
c,ta có (-5)200=(-52)100=(-25)100=25100
(-3)300=(-33)100=(-27)100=27100
Vì 25<27=>27100>25100hay (-3)100=>(-5)25
Vậy (-3)100>(-5)25