Надо ! ! вычислите: 1)77^3-69^3/70^2-62^2-77^3+41^3/125^2-49-1/2 2) 93^3-81^3/57^2-45^2-93^3-67^3/64^2-38^2+1/2

Решение смотри на фото

A³-b³=(a-b)(a²+ab+b²)
a²-b²=(a-b)(a+b

1
(77³-69³)/(70²-62²)-(77³+41³)/(125²-49)-1/2=(77-69)(77²+77*69+69²)/(70-62)(70+62)-(77+41)(77²-77*41+41²)/(125-7)(125+7) -1/2=
8*(77²+77*69+69²)/8*132-118(77²-77*41+41²)/118*132-1/2=
=(77²+77*69+69²-77²+77*41-41²)/132-1/2=
=[77*(69+41)+(69-41)(69+41)]/132-1/2=(77*110+28*110)/132-1/2=
=110*(77+28)/132-1/2=5*105/6-1/2=5*35/2-1/2=(175-1)/2=174/2=87
2
(93³-81³)/(57²-45²)-(93³-67³)/(64²-38²)+1/2=(93-81)(93²+93*81+81²)/(57-45)(57+45)-(93-67)(93²+93*67+67²)/(64-38)(64+38)+1/2=
=12*(93²+93*81+81²)/12*102-26*(93²+93*67+67²)/26*102+1/2=
=(93²+93*81+81²-93²-93*67-67²)/102+1/2=
=[(93(81-67)+(81-67)(81+67)]/102+1/2=(93*14+14*148)/102+1/2=
=14*(93+148)/102+1/2=14*241+1/2=(3374+51)/102=3425/102=33 59/102
=(93*14+14*108)/102