Question

rezolvati in multimea numerelor naturale ecuatia: xy+5x+4y=45

Answer 1

xy+5x+4y+20-20=45
x(y+5)+4(y+5)=65
(y+5)(x+4)=5*13
Avem doua situatii:
y+5=5 si x+4=13, deci y=0 si x=7
Sau:
y+5=13 si x+4=5, deci y=8 si x=1