(3/2·a + b)^3 - 3/2·a·((3/2·a + b)^2 + (a - 1/4·b)·(a + 1/4·b)+
- (a - 3/4·b)^2 + 7/3·b·(2·a + 9/8·b)) =
=(27·a^3/8 + 27·a^2·b/4 + 9·a·b^2/2 + b^3) - 3/2·a·((9·a^2/4 + 3·a·b + b^2) +
+(a^2 - b^2/16) - (a^2 - 3·a·b/2 + 9·b^2/16) + (14·a·b/3 + 21·b^2/8)) =
=(27·a^3/8 + 27·a^2·b/4 + 9·a·b^2/2 + b^3)+
- 3/2·a·(9·a^2/4 + 55·a·b/6 + 3·b^2) =
=(27·a^3/8 + 27·a^2·b/4 + 9·a·b^2/2 + b^3)+
- (27·a^3/8 + 55·a^2·b/4 + 9·a·b^2/2)=
=b^3 - 7·a^2·b