Question

Aflati a si b daca a supra b =3 supra 7 si 2a +5b= 82

Answer 1

a/b = 3/7  3b = 7a  ⇒ a = 3b/7
2a + 5b = 82
6b/7 + 5b = 82 Num. com. = 7
6b + 35b = 574
41b = 574
b = 574:41
b = 14 Inlocuim pe b in a doua relatie
2a + 5x14 = 82
2a + 70 = 82
2a = 82 - 70
2a = 12
a = 12 : 2
a = 6
Verificare: a/b = 6/14 = 3/7 si  2x6 + 5x14 = 12 + 70 = 82 Deci se verifica

Multa bafta