a) =x(1+x+x²+x³)/x(x³+x²-x-1)=simplificam cu x⇒=(1+x+x²+x³)/(x³+x²-x-1)=
=[(x³+x²)+(x+1)]/[(x³+x²)-(x+1)]=[x²(x+1)+(x+1)]/[x²(x+1)-(x+1)]=(x+1)(x²+1)/(x+1)(x²-1)=
=simplificam=(x²+1)/(x²-1)=(x²+1)/-(x²+1) simplificam=-1
b) calculam radacinile ec.de gr.II⇒(x-2)(x-3)/(x-1)(x-2) simplificam=(x-3)/(x-1)
c) idem⇒(x+4)(x+3)/(x-3)(x+3) simplificam=(x+4)/(x-3)