-t^2+78t+460=1581

解

- t^{2} + 78 t + 460 = 1581

t = 19, t = 59

解答ステップ

- t^{2} + 78 t + 460 = 1581

1581

を左側に移動します

- t^{2} + 78 t - 1121 = 0

解くとthe二次式

t_{1, 2} = \frac{- 78 \pm 7 8 ^{2} - 4 ( - 1 ) ( - 1121 )}{2 ( - 1 )}

7 8^{2} - 4 (- 1) (- 1121) = 40

t_{1, 2} = \frac{- 78 \pm 40}{2 ( - 1 )}

解を分離する

t_{1} = \frac{- 78 + 40}{2 ( - 1 )}, t_{2} = \frac{- 78 - 40}{2 ( - 1 )}

t = \frac{- 78 + 40}{2 ( - 1 )} : 19

t = \frac{- 78 - 40}{2 ( - 1 )} : 59

二次equationの解:

t = 19, t = 59