Đặt x^1000=a,y^1000=b=> ---x^2000=a^2,y^2000=b^2
\ x^3000=a^3,y^3000=b^3
Ta có: a+b=6,912
a^2+b^2=33,76244
Lại có: a+b=6,192=>a^2+b^2+2ab=6,192^2=38,340864
mà a^2+b^2=33,76244=>ab=(38,340864-33,76244)/2=2,289212
Mặt khác: a^3+b^3=(a+b)(a^2-ab+b^2)
=6,192.(33,76244-2,289212)=194,8822278