3x的平方-2x-2=0 用因式分解
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3x的平方-2x-2=0 用因式分解
![3x的平方-2x-2=0 用因式分解](/uploads/image/z/3350508-60-8.jpg?t=3x%E7%9A%84%E5%B9%B3%E6%96%B9-2x-2%3D0+%E7%94%A8%E5%9B%A0%E5%BC%8F%E5%88%86%E8%A7%A3)
3x" - 2x - 2 = 0
9x" - 6x - 6 = 0
( 9x" - 6x + 1 ) - 7 = 0
( 3x - 1 )" - (√7 )" = 0
( 3x - 1 - √7 )( 3x - 1 + √7 ) = 0
解方程得
x1 = ( 1 + √7 )/3
x2 = ( 1 - √7 )/3
9x" - 6x - 6 = 0
( 9x" - 6x + 1 ) - 7 = 0
( 3x - 1 )" - (√7 )" = 0
( 3x - 1 - √7 )( 3x - 1 + √7 ) = 0
解方程得
x1 = ( 1 + √7 )/3
x2 = ( 1 - √7 )/3