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受欢迎的代数 >

k(k+5)=19

解答

k (k + 5) = 19

解答

k = \frac{- 5 + 101}{2}, k = \frac{- 5 - 101}{2}

+1

十进制

k = 2.52493 \dots, k = - 7.52493 \dots

求解步骤

k (k + 5) = 19

展开

k (k + 5) : k^{2} + 5 k

k^{2} + 5 k = 19

将

19

para o lado esquerdo

k^{2} + 5 k - 19 = 0

使用求根公式求解

k_{1, 2} = \frac{- 5 \pm 5 ^{2} - 4 \cdot 1 \cdot ( - 19 )}{2 \cdot 1}

5^{2} - 4 \cdot 1 \cdot (- 19) = 101

k_{1, 2} = \frac{- 5 \pm 101}{2 \cdot 1}

将解分隔开

k_{1} = \frac{- 5 + 101}{2 \cdot 1}, k_{2} = \frac{- 5 - 101}{2 \cdot 1}

k = \frac{- 5 + 101}{2 \cdot 1} : \frac{- 5 + 101}{2}

k = \frac{- 5 - 101}{2 \cdot 1} : \frac{- 5 - 101}{2}

二次方程组的解是:

k = \frac{- 5 + 101}{2}, k = \frac{- 5 - 101}{2}

作图

流行的例子

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