2x平方-4x+1=2(x+?)平方+?

问题描述:

2x平方-4x+1=2(x+?)平方+?

2x²-4x+1 配方
=2(x²-2x)+1
=2(x²-2x+1)+1-2
=2(x-1)² -1
2x²-4x+1=2 [ x +(-1) ]² +(-1)