过三个平面交点的面束为(2x+y-z-2)+λ(x-3y+z+1)+μ(x+y+z-3)=0,
即:(2+λ+μ)x+(1-3λ+μ)y+(-1+λ+μ)z+(-2+λ-3μ)=0.①
为使的平面平行于平面x+y+2z-2=0,
则两个平面的法向量平行,
从而,
2+λ+μ
1
=
1?3λ+μ
1
=
?1+λ+μ
2
,
求解即得:λ=
1
19
,μ=
?4
19
.
将λ,μ的值代入①可得,
x+y+2z-4=0,
因此,所求平面为x+y+2z-4=0.