huykhang

minh vua doc yahoo hoi dap : 1 bai toan
tim nghiem nguyen phuong trinh $x^{1/2}+y^{1/2}=(x+y)^{1/2}$ minh binh phuong len giai nhung hoa ra sai! no ko tuog duong voi pt $x+2(x.y)^{1/2}+y=x+y$
nghiem cua pt kia la (0,y) (x,0)
nhung nghiem cua no lai la 9,16, ban nao giai thich ho minh cai

niu-ton la nha vat li hay toan hoc?