1.x^2-xy-2y^2=(x+y)(x-2y)=0,画x+y=0和x-2y=0的图像.
2.x^2-3ax+a^2=0,x=(3a加减根号下9a*a-4a*a)/2=(3a加减根号5a)/2
kx^2-(2k+3)x+6=(kx-3)(x-2)=0,x=3/k或2
1.x^2-xy-2y^2=(x+y)(x-2y)=0,画x+y=0和x-2y=0的图像.
2.x^2-3ax+a^2=0,x=(3a加减根号下9a*a-4a*a)/2=(3a加减根号5a)/2
kx^2-(2k+3)x+6=(kx-3)(x-2)=0,x=3/k或2