Question

aflati numerele naturale nenule care impartite la 17 dau catul de 4 ori mai mic dacat restul

Answer 1

Răspuns:

$x \in \{21,42,63,84\}$

Explicație pas cu pas:

x : 17 = y rest 4y, 4y < 17

$4y < 17, y\in \mathbb{N}\Rightarrow y \leq 4 \Rightarrow y < 4\\x = 17\cdot y + 4y = 17y + 4y = \boxed{21y = x}\Rightarrow x \in \{21k, k\in \{1,2,3,4\}\}\Rightarrow x \in\{21,42,63, 84\}$