用配方法解方程:(1)x²+(4根号2x)-1=0(2)2x²-4=7x(3)4x²-12x-1=0
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![用配方法解方程:(1)x²+(4根号2x)-1=0(2)2x²-4=7x(3)4x²-12x-1=0](/uploads/image/z/330267-3-7.jpg?t=%E7%94%A8%E9%85%8D%E6%96%B9%E6%B3%95%E8%A7%A3%E6%96%B9%E7%A8%8B%EF%BC%9A%EF%BC%881%EF%BC%89x%26%23178%3B%2B%EF%BC%884%E6%A0%B9%E5%8F%B72x%EF%BC%89-1%3D0%EF%BC%882%EF%BC%892x%26%23178%3B-4%3D7x%EF%BC%883%EF%BC%894x%26%23178%3B-12x-1%3D0)
用配方法解方程:(1)x²+(4根号2x)-1=0(2)2x²-4=7x(3)4x²-12x-1=0
用配方法解方程:(1)x²+(4根号2x)-1=0(2)2x²-4=7x(3)4x²-12x-1=0
用配方法解方程:(1)x²+(4根号2x)-1=0(2)2x²-4=7x(3)4x²-12x-1=0
(1)x²+(4根号2x)-1=0
(x+2√2)²=1+8
(x+2√2)²=9
x+2√2=±3
x=-2√2±3
2)2x²-4=7x
2x²-7x=4
x²-7/2x=2
(x-7/4)²=2+49/16
(x-7/4)²=81/16
x-7/4=±9/4
x=(7±9)/4
x=4或x=-1/2
(3)4x²-12x-1=0
x²-3x=1/4
(x-3/2)²=1/4+9/4
(x-3/2)²=10/4
x-3/2=±√10/2
x=(3±√10)/2