[Risolto] Es. N. 286

=a^4·b^2·z^4·(1/2 + 3/2·(4/9) - 2/3·(1/4))=

=a^4·b^2·z^4·(1/2 + 2/3 - 1/6)=

=a^4·b^2·z^4·1 = a^4·b^2·z^4