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a fost răspuns

a) (-2/5)^7•(+2/5)^8:(-4/25)^7

Răspuns :

Cocirmariadenis

(-2/5)⁷· (2/5)⁸:(-2²/5²)⁷=
=(-2/5)¹⁵:(-2/5)¹⁴=
=2/5
(-2/5)^7×(2/5)^8:(-1)^7(2/5)^2)^7=
(-1)^7(2/5)^15:(-1)^7(2/5)^14=
(2/5)^(15-14)=
2/5
se tine cont (-1)^7=-1 fiind putere impara