(x+1)²-3(x+1)+2=0[(x+1)²-1][(x+1)²-2]=0…………【十字相乘法】(x+1)²-1=0或(x+1)²-2=0即x+1=±1或x+1=±√2所以：x=0或x=-2或x=-1+√2或x=-1-√2
