a^2+a-1=0
a^2+a=1
(a^2+3)(a+2)-3-3a
=a^3+2a^2+3a+6-3-3a
=a^3+2a^2+3
=a^3+a^2+a^2+3
=a(a^2+a)+a^2+3
=a+a^2+3
=1+3=4