A={(x,y)｜3x+2y=0},B={(x,y)｜x-y=2},C={(x,y)｜2x-2y=3},D={(x,y)｜6x+4y=2},求A∩B,A∩C,A∩D

A={(x,y)｜3x+2y=0},B={(x,y)｜x-y=2},C={(x,y)｜2x-2y=3},D={(x,y)｜6x+4y=2},求A∩B,A∩C,A∩D
A={(x,y)｜3x+2y=0},B={(x,y)｜x-y=2},C={(x,y)｜2x-2y=3},D={(x,y)｜6x+4y=2},求A∩B,A∩C,A∩D

A={(x,y)｜3x+2y=0},B={(x,y)｜x-y=2},C={(x,y)｜2x-2y=3},D={(x,y)｜6x+4y=2},求A∩B,A∩C,A∩D
3x+2y=0
x-y=2
则5x=4,即x=4/5,代入x-y=2,y=4/5-2=-6/5
所以A∩B=（4/5,-6/5）
A∩C
3x+2y=0
2x-2y=3
则5x=3,即,x=3/5,代入2x-2y=3得：y=-9/10
A∩C=(3/5,-9/10)
A∩D
3x+2y=0
6x+4y=2
A∩D=空集,无解