((3·a - 4·b)^3 - (3·a - 5·b)^2·(3·a - 2·b) - 2·b^2·(3·a - 5·b))^2 +
+8·b^5·(3·a - 2·b) =
=((27·a^3 - 108·a^2·b + 144·a·b^2 - 64·b^3)+
- (9·a^2 - 30·a·b + 25·b^2)·(3·a - 2·b)+
- (6·a·b^2 - 10·b^3))^2 + 8·b^5·(3·a - 2·b)=
=((27·a^3 - 108·a^2·b + 144·a·b^2 - 64·b^3)+
- (27·a^3 - 108·a^2·b + 135·a·b^2 - 50·b^3)+
- (6·a·b^2 - 10·b^3))^2 + 8·b^5·(3·a - 2·b) =
=(3·a·b^2 - 4·b^3)^2 + 8·b^5·(3·a - 2·b)=
=(9·a^2·b^4 - 24·a·b^5 + 16·b^6) + (24·a·b^5 - 16·b^6) =
=9·a^2·b^4
$[(3a-4b)^3-(3a-5b)^2(3a-2b)-2b^2(3a-5b)]^2+8b^5(3a-2b)$ =
= $[27a^3-108a^2b+144ab^2-64b^3-(9a^2-30ab+25b^2)(3a-2b)-6ab^2+10b^3]^2+24ab^5-16b^6$ =
= $[27a^3-108a^2b+144ab^2-64b^3-(27a^3-18a^2b-90a^2b+60ab^2+75ab^2-50b^3)-6ab^2+10b^3]^2+24ab^5-16b^6$ =
= $[27a^3-108a^2b+144ab^2-64b^3-(27a^3-108a^2b+135ab^2-50b^3)-6ab^2+10b^3]^2+24ab^5-16b^6$ =
= $[27a^3-108a^2b+144ab^2-64b^3-27a^3+108a^2b-135ab^2-50b^3-6ab^2+10b^3]^2+24ab^5-16b^6$ =
= $[3ab^2-4b^3]^2+24ab^5-16b^6$ =
= $9a^2b^4-24ab^5+16b^6+24ab^5-16b^6$ =
= $9a^2b^4$