Question

fie a si b d.p. cu 3 si 4 , si 3a + b=39.. Aflati a si b

Answer 1

a/b = 3/4 ==> b = 4a/3
3a + b = 39
3a + 4a/3 = 39 /×3
9a + 4a = 117
13a = 117
a = 117 : 13
a = 9
b = 4×9/3 = 4×3 = 12

verificare:
3×9 + 12 = 27 + 12 = 39
9/12 = 3/4

raspuns:
a = 9
b = 12