Question

aflati x si y numere naturale prime pentru care 2x+5y=20​

Answer 1

x , y ?


2 x + 5 y = 20

x, y nat prime

Cazul 1 daca

Dacă


x = 2 x = 5
y = 5. y = 2

4 + 25 = 29 ( X). 10 + 10= 20 ( este bine)


Deci x = 5
si y = 2

Answer 2

$\it x,\ y\ numere\ prime\ \ \ \ \ (*)\\ \\ 2x+5y=20;\ \ 20\in M_2 \Rightarrow 2x+5y\in M_2 \Rightarrow 5y\in M_2\ \stackrel{(*)}{\Longrightarrow}\ y=2 \Rightarrow\\ \\ 2x+5\cdot2=20 \Rightarrow 2x+10=20 \Rightarrow 2x=10 \Rightarrow x=5$

Numerele cerute sunt: x = 5,  y = 2