b,{2x2−3x=y2−2(1)2y2−3y=x2−2(2)lay (1) -(2) ta duoc:3(x−y)(x+y−1)=0⇔x=y hoac x=1−y ket hop voi (2)giai ra duoc 4nghiem (x;y)la$(2;2), (1;1), (\frac{1+\sqrt{5}}{2};\frac{1-\sqrt{5}}{2}), (\frac{1-\sqrt{5}}{2};\frac{1+\sqrt{5}}{2})c.\Leftrightarrow {2x2+3xy+3y2=33x2+3xy+3y2=3\Leftrightarrow{2x2+3xy+3y2x=0\Leftrightarrow{x=0y=1$d.$⇔\left\{ √x+√y=4√xy=3 \right.deroitugiainhae.Dat\left\{ a=3√x+3√yb=3√xy \right.hetrothanh:\left\{ a+b=3a2−3b=3 \right.$
b,{2x2−3x=y2−2(1)2y2−3y=x2−2(2)lay (1) -(2) ta duoc:3(x−y)(x+y−1)=0⇔x=y hoac x=1−y ket hop voi (2)giai ra duoc 2nghiem (x;y)la(2;2),(1;1),c.⇔{2x2+3xy+3y2=33x2+3xy+3y2=3⇔{2x2+3xy+3y2x=0⇔{x=0y=1d.⇔{√x+√y=4√xy=3 de roi tu giai nhae.Dat{a=3√x+3√yb=3√xy he tro thanh :{a+b=3a2−3b=3