用一元二次方程解:(1) 2x²-4x+1=0 (2) 2y²-7y+3=0 (3) 2x²-12x+7=0
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![用一元二次方程解:(1) 2x²-4x+1=0 (2) 2y²-7y+3=0 (3) 2x²-12x+7=0](/uploads/image/z/806684-68-4.jpg?t=%E7%94%A8%E4%B8%80%E5%85%83%E4%BA%8C%E6%AC%A1%E6%96%B9%E7%A8%8B%E8%A7%A3%EF%BC%9A%281%29+2x%26%23178%3B-4x%2B1%3D0+%282%29+2y%26%23178%3B-7y%2B3%3D0+%283%29+2x%26%23178%3B-12x%2B7%3D0)
用一元二次方程解:(1) 2x²-4x+1=0 (2) 2y²-7y+3=0 (3) 2x²-12x+7=0
用一元二次方程解:(1) 2x²-4x+1=0 (2) 2y²-7y+3=0 (3) 2x²-12x+7=0
用一元二次方程解:(1) 2x²-4x+1=0 (2) 2y²-7y+3=0 (3) 2x²-12x+7=0
(1) 2x²-4x+1=0
x²-2x+1/2=0
x²-2x+1-1+1/2=0
(x-1)²=1/2
x-1=±√2/2
x=1±√2/2
(2)2y²-7y+3=0
(y-3)(2y-1)=0
y-3=0 或 2y-1=0,即 y=3 或 y=1/2
(3) 2x²-12x+7=0
x²-12x+36-36+7=0
(x-6)²=29
x-6=±√29
x=6±√29