х²+х-1

Объяснение:

(x²-3x+1)+(-x²+x-1)-(1-3x-x²)=х²-3х+1-х²+х-1-1+3х+х²

Verified answer

Ответ:      

(x2−3x+1)+(−x2+x−1)−(1−3x−x2)=

x2−3x+1+(−x2+x−1)−(1−3x−x2)=

x2−3x+1−x2+x−1−(1−3x−x2)=

−2x−(1−3x−x2)=

−2x−1+3x+x2=

x−1+x2