Chứng minh rằng

B.5. Cluing minly ziang
3
A = n³ + (n + 1)³ + (n+ 2)³: 9(+nez)
A 1 = n/3√²-1) -3n (²n-2):51 +nek)
(3
A = n($u+5) - (n-3) (n+2):6 (Unitz)
A = (4² +3y-1) (h+2) -4³ +2:5( 4 nez)
A = (2n+1) (4² -34 -1)^2n³t 1:5 (tinez
A 37 / 11 -1) (171) - (11-1)/11-3)) : 812 / Une 2) =
A=
A = (5 g -3) (36-5)-(3 a 5) (Gb~3):16)
( aj bek)
(2)