cat face 1 supra 2 + 7 supra 5 in paranteza -1 supra 3

(1/2+7/5)(-1/3)=
=(1/2^15+7/5^6)(-1/3^10)=
=(15/30+42/30)(-10/30)=
=57/30-10/30=
=47/30
Sper că e corect !!!