Question

[Nguyễn Thị Vân Anh]

tính
a)  (y-1).(y2+y+1)+(1/3.x2y-y).(2x+y2) 

b) (x-1).(x-3)-(4-x).(2x+1)-3x2+2x-5

e) 2x2+3.(x-1).(x+1)-5x.(x+1)

f)  4.(x-1) .(x+5)-(x+2).(x+5)-3.(x-1).(x+2)

g)  (x+2).(x2+2x+4)-(x-2)3-6.(x-1).(x+1)