Ta có :.$\left \{ {{(-2x-8)} \atop {(3y+9)}} \right.$ = 0
TH1 : ( -2x -8) = 0 => -2x = 0 + 8 => -2x = 8 => x = 8 : -2 => x = (-4)
TH2 : 3y + 9 = 0 => 3y = 0-9 => 3y = (-9) => y = (-9) : 3 => y = (-3)
Vậy $\left \{ {{x = (-4) } \atop {y=(-3)}} \right.$