0.345=a 1.345=a+1 2.69=2(a+1)1.345×0.345×2.69-1.345³-1.345×0.345²=(a+1)*a*2(a+1)-(a+1)^3-(a+1)*a^2=2a(a+1)^2-(a+1)^3-a^2(a+1)=(a+1)[2a(a+1)-(a+1)^2-a^2]=-(a+1)= -1.345