r^2+7r+12=0

解

r^{2} + 7 r + 12 = 0

r = - 3, r = - 4

解答ステップ

r^{2} + 7 r + 12 = 0

解くとthe二次式

r_{1, 2} = \frac{- 7 \pm 7 ^{2} - 4 \cdot 1 \cdot 12}{2 \cdot 1}

7^{2} - 4 \cdot 1 \cdot 12 = 1

r_{1, 2} = \frac{- 7 \pm 1}{2 \cdot 1}

解を分離する

r_{1} = \frac{- 7 + 1}{2 \cdot 1}, r_{2} = \frac{- 7 - 1}{2 \cdot 1}

r = \frac{- 7 + 1}{2 \cdot 1} : - 3

r = \frac{- 7 - 1}{2 \cdot 1} : - 4

二次equationの解:

r = - 3, r = - 4