m^2-m-20=0

解

m^{2} - m - 20 = 0

m = 5, m = - 4

解答ステップ

m^{2} - m - 20 = 0

解くとthe二次式

m_{1, 2} = \frac{- ( - 1 ) \pm ( - 1 ) ^{2} - 4 \cdot 1 \cdot ( - 20 )}{2 \cdot 1}

(- 1)^{2} - 4 \cdot 1 \cdot (- 20) = 9

m_{1, 2} = \frac{- ( - 1 ) \pm 9}{2 \cdot 1}

解を分離する

m_{1} = \frac{- ( - 1 ) + 9}{2 \cdot 1}, m_{2} = \frac{- ( - 1 ) - 9}{2 \cdot 1}

m = \frac{- ( - 1 ) + 9}{2 \cdot 1} : 5

m = \frac{- ( - 1 ) - 9}{2 \cdot 1} : - 4

二次equationの解:

m = 5, m = - 4