x2-1x3-1×y3-1y2-1×x4+x2+1x4+y2+1= কত?
ক
x2-x+1y2-y+1
খ
x+1y+1
গ
x3+1y3+1
ঘ
x3-1y3-1
সঠিক উত্তর: x3+1y3+1
