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Florentinaconst
a fost răspuns

media ponderata  a numerelor a=4,2 si b=3,5(3)cu ponderile 7 si 3.

Răspuns :

b=3,5(3)=(353-35)/90=318/90=simplif=159/45=53/15
a=4,2=42/10=simplif=21/5
Mp=(7x21/5+3x53/15)/(7+3)=(147/5+159/15)/10=[(147x3+159)/15]/10=
=[(441+159)/15]/10=600/(15x10)=600/150=60/15=4