已知x1,x2是方程x²-2x+a=0的两个实数根,且x1+2x2=3-根号2

x1,x2是方程x²-2x+a=0的两个实数根所以x1+x2=2因为x1+2x2=3-√2所以x2=1-√2,x1=1+√2x1x2=aa=(1+√2)(1-√2)=-1x1^3+3x1²+2x1+x2=x1(x1+1)(x1+2)+x2=(1+√2)(2+√2)(3+√2)+1-√2=14+14√2+1-√2=15+13√...