Question

Sa se determine multimea X={(x,y)/x,y €N,5x+6y=70}

Answer 1

5x+6y=70

6y=70-5x

y=(70-5x)/6
y={N}, rezulta 6 divide 70-5x si 70-5x>=0, adica x<=14

x=1, y=Q
x=2, y=10, solutie
x=3, y=Q
...
x=8, y=5
...
x=14, y=0

Pt. celelalte valori ale lui x, y=Q

X={(2;10),(8;5),(14;0)}