ederly muon ********

fix

she has to finish a assignments this afternoon

minh ko ghi dc chuc ban may man sorry

ai ma viet ra dc

thi thu de hon thi that no chi giong vai cau thoi

sap thi cap huyen roi dc cai gi ma dc

x³-x+y³-y=(x³+y³)+(-x-y)=(x+y)(x²-xy+y²)-(x+y)=(x+y)(x²-xy+y²-1)

thanks