3x^2-12x+9=0

解答

3 x^{2} - 12 x + 9 = 0

x = 3, x = 1

求解步骤

3 x^{2} - 12 x + 9 = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 12 ) \pm ( - 12 ) ^{2} - 4 \cdot 3 \cdot 9}{2 \cdot 3}

(- 12)^{2} - 4 \cdot 3 \cdot 9 = 6

x_{1, 2} = \frac{- ( - 12 ) \pm 6}{2 \cdot 3}

将解分隔开

x_{1} = \frac{- ( - 12 ) + 6}{2 \cdot 3}, x_{2} = \frac{- ( - 12 ) - 6}{2 \cdot 3}

x = \frac{- ( - 12 ) + 6}{2 \cdot 3} : 3

x = \frac{- ( - 12 ) - 6}{2 \cdot 3} : 1

二次方程组的解是:

x = 3, x = 1