7x^2+28x-35=0

解

7 x^{2} + 28 x - 35 = 0

x = 1, x = - 5

解答ステップ

7 x^{2} + 28 x - 35 = 0

解くとthe二次式

x_{1, 2} = \frac{- 28 \pm 2 8 ^{2} - 4 \cdot 7 ( - 35 )}{2 \cdot 7}

2 8^{2} - 4 \cdot 7 (- 35) = 42

x_{1, 2} = \frac{- 28 \pm 42}{2 \cdot 7}

解を分離する

x_{1} = \frac{- 28 + 42}{2 \cdot 7}, x_{2} = \frac{- 28 - 42}{2 \cdot 7}

x = \frac{- 28 + 42}{2 \cdot 7} : 1

x = \frac{- 28 - 42}{2 \cdot 7} : - 5

二次equationの解:

x = 1, x = - 5