solvefor x,x^2-3kx+9=0

解

x, x^{2} - 3 k x + 9 = 0

x = \frac{3 k + 3 k ^{2} - 4}{2}, x = \frac{3 k - 3 k ^{2} - 4}{2}

解答ステップ

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

解くとthe二次式

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

簡素化

(- 3 k)^{2} - 4 \cdot 1 \cdot 9 : 3 k^{2} - 4

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

解を分離する

x_{1} = \frac{- ( - 3 k ) + 3 k ^{2} - 4}{2 \cdot 1}, x_{2} = \frac{- ( - 3 k ) - 3 k ^{2} - 4}{2 \cdot 1}

x = \frac{- ( - 3 k ) + 3 k ^{2} - 4}{2 \cdot 1} : \frac{3 k + 3 k ^{2} - 4}{2}

x = \frac{- ( - 3 k ) - 3 k ^{2} - 4}{2 \cdot 1} : \frac{3 k - 3 k ^{2} - 4}{2}

二次equationの解:

x = \frac{3 k + 3 k ^{2} - 4}{2}, x = \frac{3 k - 3 k ^{2} - 4}{2}