quadraticformula x^2-4x=5

解

x^{2} - 4 x = 5

x = 5, x = - 1

解答ステップ

x^{2} - 4 x = 5

5

を左側に移動します

x^{2} - 4 x - 5 = 0

解くとthe二次式

x_{1, 2} = \frac{- ( - 4 ) \pm ( - 4 ) ^{2} - 4 \cdot 1 \cdot ( - 5 )}{2 \cdot 1}

(- 4)^{2} - 4 \cdot 1 \cdot (- 5) = 6

x_{1, 2} = \frac{- ( - 4 ) \pm 6}{2 \cdot 1}

解を分離する

x_{1} = \frac{- ( - 4 ) + 6}{2 \cdot 1}, x_{2} = \frac{- ( - 4 ) - 6}{2 \cdot 1}

x = \frac{- ( - 4 ) + 6}{2 \cdot 1} : 5

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

二次equationの解:

x = 5, x = - 1