2x²-5x+1=0用配方法做,要经检验
1个回答

2x²-5x+1=0

2(x²-5x/2+25/16)-2*25/16+1=0

2(x-5/4)²=25/8+1

(x-5/4)²=33/16

x-5/4=±√33/4

x=5/4±√33/4

x1=(5+√33)/4

x2=(5-√33)/4

检验:

将x1=(5+√33)/4 代人2x²-5x+1=0得

2*(25+33+10√33)/16-5(5+√33)/4 +1=0

满足方程

所以所求为原方程的根