r^2-9r-10=0

解

r^{2} - 9 r - 10 = 0

r = 10, r = - 1

解答ステップ

r^{2} - 9 r - 10 = 0

解くとthe二次式

r_{1, 2} = \frac{- ( - 9 ) \pm ( - 9 ) ^{2} - 4 \cdot 1 \cdot ( - 10 )}{2 \cdot 1}

(- 9)^{2} - 4 \cdot 1 \cdot (- 10) = 11

r_{1, 2} = \frac{- ( - 9 ) \pm 11}{2 \cdot 1}

解を分離する

r_{1} = \frac{- ( - 9 ) + 11}{2 \cdot 1}, r_{2} = \frac{- ( - 9 ) - 11}{2 \cdot 1}

r = \frac{- ( - 9 ) + 11}{2 \cdot 1} : 10

r = \frac{- ( - 9 ) - 11}{2 \cdot 1} : - 1

二次equationの解:

r = 10, r = - 1