Y xy 2 5 x 7 July 8, 2019 16 32 64 128 Y xy 2 5 x 7 click to select points on the graph Xy 5 x 2 2xy y 2 =- 7 Y =- xy 2 5x 7 5 x 2 xy y 2 )= 7 x 2y X y 2 /- 5 và xy =- 7 X y 7 2 xy 5 2 find x2 y2 X+y 2 5+z xy