Note that: (x^3+y^3)(x^6-(xy)^3+y^6) = 19(x^6-(xy)^3+y^6) = x^9+y^9
I (x^3+y^3) - (x+y)^3 =18; 3xy(x+y) = 3xy = -18; so xy = -6II (x^3+y^3)^2 = 19^2 = x^6+2(xy)^3+y^6; so (x^6-(xy)^3+y^6) = 19^2-3(-6)^3 = 1009III (from I) (19)(1009) = 19171 = x^9+y^9
Edited on October 24, 2016, 11:14 am
blackjack
flooble's webmaster puzzle