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a fost răspuns

3 stilouri si 4 carti costa 120000 lei. 7 stilouri si 3 carti costa 185000lei. Cat costa un stilou si cat costa o carte

Răspuns :

3s+4c=120000, 3s=120000-4c, s=(120000-4c)/3 il introducem pe s in a doua relatie

7s+3c=185000, 7(120000-4c)/3+3c=185000, numitor comun 3

7(120000-4c)+9c=555000

840000-28c+9c=555000

19c=840000-555000=285000

c=285000/19=15000lei

s=(120000-4*15000)/3=(120000-60000)/3=60000/3=20000lei

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