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Cristinaiepurica
a fost răspuns

Calculeaza folosind factor comun :7xa +9×b+2×c daca a+b=43 si b+c=15

Răspuns :

Didi12342
a + b = 43
b + c = 15
7×a + 9×b + 2 ×c =
= 7×a + 7×b + 2×b + 2×c =
= 7 × (a+b) + 2 × (b + c) =
= 7 × 43 + 2 × 15 =
= 301 + 30 =
= 331