y^2-10y+21=0

解

y^{2} - 10 y + 21 = 0

y = 7, y = 3

解答ステップ

y^{2} - 10 y + 21 = 0

解くとthe二次式

y_{1, 2} = \frac{- ( - 10 ) \pm ( - 10 ) ^{2} - 4 \cdot 1 \cdot 21}{2 \cdot 1}

(- 10)^{2} - 4 \cdot 1 \cdot 21 = 4

y_{1, 2} = \frac{- ( - 10 ) \pm 4}{2 \cdot 1}

解を分離する

y_{1} = \frac{- ( - 10 ) + 4}{2 \cdot 1}, y_{2} = \frac{- ( - 10 ) - 4}{2 \cdot 1}

y = \frac{- ( - 10 ) + 4}{2 \cdot 1} : 7

y = \frac{- ( - 10 ) - 4}{2 \cdot 1} : 3

二次equationの解:

y = 7, y = 3