Решите уравнение: (1+x+x2)(1+x+x2+x3+x4)=(1+x+x2+x3)2.\left( 1+x+{{x}^{2}} \right)\left( 1+x+{{x}^{2}}+{{x}^{3}}+{{x}^{4}} \right)={{\left( 1+x+{{x}^{2}}+{{x}^{3}} \right)}^{2}}.(1+x+x2)(1+x+x2+x3+x4)=(1+x+x2+x3)2.