=-a^3-3a^2+7a-8-3a^3+2a^2+5a-2+a^3+2a^2+4
=-3a^3+a^2+ 12a-6
=a^2(-3a+ 1)+6(2a- 1)
= 1/4*(-3/2+ 1)+0
=-( 1/4)*( 1/2)
=- 1/8
I wish you happiness.