Răspuns:
(-8)^7×[-5/3]^21
= ('8)⁷ × (-5/3)²¹
=(-8)⁷ × (-5/3)⁷˟³
=(-8)⁷×[(-5/3)³]⁷
=(-8)⁷×(-125/27)⁷
=[-8×(-125/27)]⁷
=(8×125/27)⁷
=(1000/27)⁷
=1000⁷/27⁷
=(10³)⁷/(3³)⁷
=10²¹/3²¹
=(10/3)²¹
