2x-y=3 y=2x-3
把 y=2x-3代入y^2+4x-3y=6得
（2x-3)^2+4x-3(2x-3)=6
4x^2-14x+12=0
2x^2-7x+6=0
(2x-3)(x-2)=0
x1=3/2 x2=2
y1=0 y2=1