Question

Пусть х1+х2=7; х1х2=2. Найти: х1^3×х2^6+х1^6×х2^3​

Answer 1

x1³x2³(x2³+x1³)

(x1+x2)³=7³

x1³+3x1²x2+3x1x2²+x2³=343

x1³+x2³=343-3x1x2(x1+x2)

x1³+x2³=343-3*2*7

x1³+x2³=301

x1³x2³=8

x1³x2³(x2³+x1³)= 8*301= 2408