2x^2-3x-7=0
2(x^2-2X3/4x+(3/4)^2)-7-9/8=0
2(x-3/4)^2=65/8
(x-3/4)^2=65/16
x-3/4=±根号65/4
x=±根号65/4+3/4
2x方-3x-7=0（使用配方法）
2x^2-3x-7=0
2(x^2-2X3/4x+(3/4)^2)-7-9/8=0
2(x-3/4)^2=65/8
(x-3/4)^2=65/16
x-3/4=±根号65/4
x=±根号65/4+3/4