Question

4x²-6x－3=0,用配方法怎么解？

4x²-6x-3=0怎么解，急

Answer 1

4x²-6x－3=0
x²-3x/2=3/4
x²-3x/2+9/16=3/4+9/16
（x-3/4）^2=21/16
x-3/4=±（√21)/4,
x=(3±√21)/4

Answer 2

用配方法：
4x²-6x-3=0
(2x)²-2*2x*3/2+(3/2)²-(3/2)²-3=0
(2x-3/2)²=3+(3/2)²
(2x-3/2)²=12/4+9/4
(2x-3/2)²=21/4
2x-3/2=±√(21/4)
2x-3/2=±√21/2
2x=3/2±√21/2
x=(3±√21)/4
所以方程的解是：x=(3±√21)/4