用配方法:2x²-5x-3=0

问题描述:

用配方法:2x²-5x-3=0

2x²-5x-3=0
2(x²-5/2x)=3
2(x²-5/2x+25/16)=3+25/8
2(x-5/4)²=49/8
(x-5/4)²=49/16=(7/4)²
x-5/4=±7/4
x=3或x=-1/2