`{(3x+y=2\sqrt{2}),(-\sqrt{2}x+y=1):}`
`<=>{(3x+y+\sqrt{2}x-y=2\sqrt{2}-1),(-\sqrt{2}x+y=1):}`
`<=>{(3x+\sqrt{2}x=2\sqrt{2}-1),(-\sqrt{2}x+y=1):}`
`<=>{(x(3+\sqrt{2})=2\sqrt{2}-1),(-\sqrt{2}x+y=1):}`
`<=>{(x=-1+\sqrt{2}),(-\sqrt{2}(-1+\sqrt{2})+y=1):}`
`<=>{(x=-1+\sqrt{2}),((-2+\sqrt{2})+y=1):}`
`<=>{(x=-1+\sqrt{2}),(y={-2+\sqrt{2}}/2):}`
Vậy hpt có nghiệm `(x; y)=(-1+\sqrt{2}; {-2+\sqrt{2}}/2)`