有韦达定理得：x1 + x2 = -1x1 * x2 = -3所以(x1-x2)^2 = (x1+x2)^2 - 4x1x2 = 1 + 12 = 13故|x1-x2| = 根号13因为x1是原方程的根,所以(x1)^2+x1-3=0即(x1)^2 + x1 = 3因此(x1)^2 + 2x1 + x2= (x1)^2 + x1 + (x1+x2)...