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Consideram numerele rationale a,b si c.Se stie ca a*b=[tex] 2 \frac{3}{7} si  a * c= - \frac{3}{14} [/tex]
a.Calculati a*(b+c) si a *(b-c)
b.Daca b+c=[tex] \frac{31}{7} [/tex],calculati a.


Răspuns :

ab=2intregi3/7
ab=(2x7+3)/7
ab=17/7
ac=-3/14
a) a(b+c)=ab+ac=17/7-3/14=(17x2-3)/14=(34-3)/14=31/14=2,2(142857)

a(b-c)=ab-ac=17/7-(-3/14)=17/7+3/14=(17x2+3)/14=37/14=2,6(428571)