Question

解方程组x²-3xy+2y²=0 x²+3y²=4

Answer 1

x²-3xy+2y²=0

（x-y)(x-2y)=0

x=y

x=2y

代入：y²+3y²=4

y²=1

y=±1

x=±1

即X=1,y=1

x=-1,y=-1

(2)(2y)²+3y²=4

y²=4/7

y=±2√7/7

x=±4√7/7

即X=4√7/7,y=2√7/7

X=-4√7/7,y=-2√7/7