(7/2 - 1/4·a)·(7/2 + 1/4·a) + a^2·((a - 2)·(a + 2)) - (2·a - 1/2)·((a - 2)/2)·(2·a + 1/2)·(a/2 + 1)=
=(49/4 - a^2/16) + a^2·(a^2 - 4) - ((2·a - 1/2)·(2·a + 1/2))·((a - 2)/2·((a + 2)/2))=
=(49/4 - a^2/16) + (a^4 - 4·a^2) - (4·a^2 - 1/4)·(a^2/4 - 1)=
=((49/4 - a^2/16) + (a^4 - 4·a^2)) - (a^4 - 65·a^2/16 + 1/4)=
=(a^4 - 65·a^2/16 + 49/4) - (a^4 - 65·a^2/16 + 1/4)=
= 12