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受欢迎的代数 >

x^2+sqrt(5)x+1=0

解答

x^{2} + 5 x + 1 = 0

解答

x = \frac{- 5 + 1}{2}, x = \frac{- 5 - 1}{2}

+1

十进制

x = - 0.61803 \dots, x = - 1.61803 \dots

求解步骤

x^{2} + 5 x + 1 = 0

使用求根公式求解

x_{1, 2} = \frac{- 5 \pm ( 5 ) ^{2} - 4 \cdot 1 \cdot 1}{2 \cdot 1}

(5)^{2} - 4 \cdot 1 \cdot 1 = 1

x_{1, 2} = \frac{- 5 \pm 1}{2 \cdot 1}

将解分隔开

x_{1} = \frac{- 5 + 1}{2 \cdot 1}, x_{2} = \frac{- 5 - 1}{2 \cdot 1}

x = \frac{- 5 + 1}{2 \cdot 1} : \frac{- 5 + 1}{2}

x = \frac{- 5 - 1}{2 \cdot 1} : \frac{- 5 - 1}{2}

二次方程组的解是:

x = \frac{- 5 + 1}{2}, x = \frac{- 5 - 1}{2}

作图

流行的例子

solvefor t,-4.905t^2-0.517t-15=0

so l v e f or t, - 4.905 t^{2} - 0.517 t - 15 = 0

k^{2} + 5 k = 14

x^{2} - 4 x - 70 = 80 + x

- 4 x^{2} - 3 x - 1 = 0

(5 x - 2)^{2} = 36