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受欢迎的代数 >

3k^2-14k-21=0

解答

3 k^{2} - 14 k - 21 = 0

解答

k = \frac{7 + 4 7}{3}, k = \frac{7 - 4 7}{3}

+1

十进制

k = 5.86100 \dots, k = - 1.19433 \dots

求解步骤

3 k^{2} - 14 k - 21 = 0

使用求根公式求解

k_{1, 2} = \frac{- ( - 14 ) \pm ( - 14 ) ^{2} - 4 \cdot 3 ( - 21 )}{2 \cdot 3}

(- 14)^{2} - 4 \cdot 3 (- 21) = 87

k_{1, 2} = \frac{- ( - 14 ) \pm 8 7}{2 \cdot 3}

将解分隔开

k_{1} = \frac{- ( - 14 ) + 8 7}{2 \cdot 3}, k_{2} = \frac{- ( - 14 ) - 8 7}{2 \cdot 3}

k = \frac{- ( - 14 ) + 8 7}{2 \cdot 3} : \frac{7 + 4 7}{3}

k = \frac{- ( - 14 ) - 8 7}{2 \cdot 3} : \frac{7 - 4 7}{3}

二次方程组的解是:

k = \frac{7 + 4 7}{3}, k = \frac{7 - 4 7}{3}

作图

流行的例子

solvefor x,x^2+2kx-3=kx^2+1.4

so l v e f or x, x^{2} + 2 k x - 3 = k x^{2} + 1.4

solvefor t,s= 1/6 gt^2

so l v e f or t, s = \frac{1}{6} g t^{2}

7 x^{2} - 200 = 24

25 - 4 x^{2} = 0

12x^2+18x=(12x+18)

12 x^{2} + 18 x = (12 x + 18)