Question

已知,x^2 -xy-2y^2 =x-2y,且x-2y不等于0,则(1)x+y=________(2若题中)x、y满足等

Answer 1

x²-xy-2y²=x-2y

x²-xy-2y²-(x-2y)=0

(x-2y)(x+y)-(x-2y)=0

(x-2y)(x+y-1)=0

x-2y≠0,因此只有x+y-1=0

x+y=1

y=1-x

x²+y²-9x+5y+26=0

y=1-x代入,整理,得

x²-8x+16=0

(x-4)²=0

x=4

y=1-x=1-4=-3

x=4 y=-3