方程2（x+3）²=x（x+3)移项得：2(x+3)²- x(x+3)=0(x+3)(2x+6-x)=0(x+3)(x+6)=0解得：x=-3或x=-6.方程x²-2根号下5x +2=0配方得：x²- 2根号5*x+5 -3=0(x- 根号5)²=3解得：x-根号5=根号3或x-...