x^2-80x+1200=0

解

x^{2} - 80 x + 1200 = 0

x = 60, x = 20

解答ステップ

x^{2} - 80 x + 1200 = 0

解くとthe二次式

x_{1, 2} = \frac{- ( - 80 ) \pm ( - 80 ) ^{2} - 4 \cdot 1 \cdot 1200}{2 \cdot 1}

(- 80)^{2} - 4 \cdot 1 \cdot 1200 = 40

x_{1, 2} = \frac{- ( - 80 ) \pm 40}{2 \cdot 1}

解を分離する

x_{1} = \frac{- ( - 80 ) + 40}{2 \cdot 1}, x_{2} = \frac{- ( - 80 ) - 40}{2 \cdot 1}

x = \frac{- ( - 80 ) + 40}{2 \cdot 1} : 60

x = \frac{- ( - 80 ) - 40}{2 \cdot 1} : 20

二次equationの解:

x = 60, x = 20