2) а+3 - а²-5 - 2а³-а(1-5а)-1 =
2а-1 4а²-4а+1 8а³-12а²+6а-1
= а+3 - а²-5 - 2а³-а+5а²-1 =
2а-1 (2а-1)² (2а-1)³
=(а+3)(2а-1)²-(а²-5)(2а-1)-(2а³-а+5а²-1) =
(2а-1)³
=(а+3)(4а²-4а+1)-(2а³-10а-а²+5)-2а³+а-5а²+1 =
(2а-1)³
=4а³+12а²-4а²-12а+а+3-2а³+10а+а²-5-2а³+а-5а²+1=
(2а-1)³
= 4а²-1 = (2а-1)(2а+1)=2а+1 = 2а+1
(2а-1)³ (2а-1)³ (2а-1)² 4а²-4а+1