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受欢迎的代数 >

-300=17t-4.9t^2

解答

- 300 = 17 t - 4.9 t^{2}

解答

t = - \frac{5 ( 6169 - 17 )}{49}, t = \frac{5 ( 17 + 6169 )}{49}

+1

十进制

t = - 6.27989 \dots, t = 9.74928 \dots

求解步骤

- 300 = 17 t - 4.9 t^{2}

在两边乘以

10

- 3000 = 170 t - 49 t^{2}

交换两边

170 t - 49 t^{2} = - 3000

将

3000

para o lado esquerdo

170 t - 49 t^{2} + 3000 = 0

改写成标准形式

a x^{2} + b x + c = 0

- 49 t^{2} + 170 t + 3000 = 0

使用求根公式求解

t_{1, 2} = \frac{- 170 \pm 17 0 ^{2} - 4 ( - 49 ) \cdot 3000}{2 ( - 49 )}

17 0^{2} - 4 (- 49) \cdot 3000 = 106169

t_{1, 2} = \frac{- 170 \pm 10 6169}{2 ( - 49 )}

将解分隔开

t_{1} = \frac{- 170 + 10 6169}{2 ( - 49 )}, t_{2} = \frac{- 170 - 10 6169}{2 ( - 49 )}

t = \frac{- 170 + 10 6169}{2 ( - 49 )} : - \frac{5 ( 6169 - 17 )}{49}

t = \frac{- 170 - 10 6169}{2 ( - 49 )} : \frac{5 ( 17 + 6169 )}{49}

二次方程组的解是:

t = - \frac{5 ( 6169 - 17 )}{49}, t = \frac{5 ( 17 + 6169 )}{49}

作图

流行的例子

3 p^{2} - 13 p + 4 = - 4

(x) (x + 1) = 240

5 x^{2} + 5 x - \frac{3}{4} = 0

因式分解 3x^2+12x=7x+2

f a c t or 3 x^{2} + 12 x = 7 x + 2

x^{2} - 18 x + 60 = - 21