Răspuns: 90 numere
Explicație pas cu pas:
xyz÷(2×xy+1)=z=>xyz=z×(2×xy+1)
xy0+z=z×(2×xy+1)
xy0+z=z×2×xy+z/-z
xy0=z×2×xy
100x+10y+0=z×2×(10x+y)
100x+10y+0=z×(20x+2y)/-0
100x+10y=z×(20x+2y)
z×20x=100x=>z=100x÷20x=>z=5
z×2y=10y=>z=10y÷2y=>z=5
=>x={1, 2, 3, 4, 5, 6, 7, 8, 9}-->9 valori
=>y={0, 1, 2, 3, 4, 5, 6, 7, 8, 9}-->10 valori
9×10=90 (numere)
