solvefor x,x^2-2x=8

解

x, x^{2} - 2 x = 8

x = 4, x = - 2

解答ステップ

x^{2} - 2 x = 8

8

を左側に移動します

x^{2} - 2 x - 8 = 0

解くとthe二次式

x_{1, 2} = \frac{- ( - 2 ) \pm ( - 2 ) ^{2} - 4 \cdot 1 \cdot ( - 8 )}{2 \cdot 1}

(- 2)^{2} - 4 \cdot 1 \cdot (- 8) = 6

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

解を分離する

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

x = \frac{- ( - 2 ) + 6}{2 \cdot 1} : 4

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

二次equationの解:

x = 4, x = - 2