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受欢迎的代数 >

78=7t+16t^2

解答

78 = 7 t + 16 t^{2}

解答

t = 2, t = - \frac{39}{16}

+1

十进制

t = 2, t = - 2.4375

求解步骤

78 = 7 t + 16 t^{2}

交换两边

7 t + 16 t^{2} = 78

将

78

para o lado esquerdo

7 t + 16 t^{2} - 78 = 0

改写成标准形式

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

16 t^{2} + 7 t - 78 = 0

使用求根公式求解

t_{1, 2} = \frac{- 7 \pm 7 ^{2} - 4 \cdot 16 ( - 78 )}{2 \cdot 16}

7^{2} - 4 \cdot 16 (- 78) = 71

t_{1, 2} = \frac{- 7 \pm 71}{2 \cdot 16}

将解分隔开

t_{1} = \frac{- 7 + 71}{2 \cdot 16}, t_{2} = \frac{- 7 - 71}{2 \cdot 16}

t = \frac{- 7 + 71}{2 \cdot 16} : 2

t = \frac{- 7 - 71}{2 \cdot 16} : - \frac{39}{16}

二次方程组的解是:

t = 2, t = - \frac{39}{16}

作图

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