Question

Determinati x, y aprtin lui N, stiind ca 3xy-2y=38 si xy+2=16

Answer 1

xy+2=16 I*3⇒3xy+6=48⇒3xy=48-6⇒3xy=42
3xy-2y=38⇒42-2y=38⇒2y=42-38⇒2y=4⇒y=2
xy+2=16⇒2x+2=16⇒2x=16-2⇒2x=14⇒x=14/2⇒x=7

Answer 2

xy+2=16 => xy=16-2=14
3xy-2y=38,inlocuim xy cu 14 ,astfel primim 3*14-2y=38 => 42-2y=38 . Aflam pe y : y=(42-38)/2=2.
Aflam pe x: 3xy-2y=38 => 6x-4=38 => x=(38+4)/6=7
R/S: x=7,y=2.