Răspuns:
Explicație pas cu pas:
a + b + c = 138
a : 5 = c rest r
b : 6 = c rest r
c : 7 = c rest r
_____________
=> a = 5 × c + r
b = 6 × c + r
c = 7 × c + r
_____________ le adun
a + b + c = 138
(5 × c + r) + ( 6 × c + r ) +( 7 × c + r) = 138
18 × c + 3 × r = 138 l : 3
6 × c + rest = 46 ; restul < 5
6 × c = 46 - rest ( diferenta ∈ M₆= 42 ) => restul = 4 < 5
6 × c = 46 - 4
c = 42 : 6 ⇒ c = 7 ( catul )
_______________________
a = 5 × 7 + 4 ⇒ a = 39
b = 6 × 7 + 4 ⇒ b = 46
c = 7 × 7 + 4 ⇒ c = 53
__________________
Verific:
39 + 46 + 53 = 138 -> suma celor trei numere
