用配方法解:6y²-y-12=0
问题描述:
用配方法解:6y²-y-12=0
4x²-12x-1=0
答
6y²-y-12=0
y²-y/6-2=0
y²-y/6+(1/12)²=2+1/144
(y-1/12)²=289/144
y-1/12=±17/12
y=1/12±17/12
y1=3/2 y2=-4/3
4x²-12x-1=0
x²-3x-1/4=0
x²-3x-(3/2)²=1/4+9/4
(x-3/2)²=10/4
x-3/2=±√10/2
x=3/2±√10/2
x1=(3+√10)/2 x1=(3-√10)/2