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受欢迎的代数 >

4.9x^2+8x-30=0

解答

4.9 x^{2} + 8 x - 30 = 0

解答

x = \frac{10 ( 163 - 4 )}{49}, x = - \frac{10 ( 4 + 163 )}{49}

+1

十进制

x = 1.78921 \dots, x = - 3.42186 \dots

求解步骤

4.9 x^{2} + 8 x - 30 = 0

在两边乘以

10

49 x^{2} + 80 x - 300 = 0

使用求根公式求解

x_{1, 2} = \frac{- 80 \pm 8 0 ^{2} - 4 \cdot 49 ( - 300 )}{2 \cdot 49}

8 0^{2} - 4 \cdot 49 (- 300) = 20163

x_{1, 2} = \frac{- 80 \pm 20 163}{2 \cdot 49}

将解分隔开

x_{1} = \frac{- 80 + 20 163}{2 \cdot 49}, x_{2} = \frac{- 80 - 20 163}{2 \cdot 49}

x = \frac{- 80 + 20 163}{2 \cdot 49} : \frac{10 ( 163 - 4 )}{49}

x = \frac{- 80 - 20 163}{2 \cdot 49} : - \frac{10 ( 4 + 163 )}{49}

二次方程组的解是:

x = \frac{10 ( 163 - 4 )}{49}, x = - \frac{10 ( 4 + 163 )}{49}

作图

流行的例子

(2 x + 2)^{2} - 12 = 4

u^{2} + 4 u + 3 = 0

- 3 x + x^{2} - 4 = - 8 + x

因式分解 6x^2-x-15=0

f a c t or 6 x^{2} - x - 15 = 0

(x - 9) (x + 7) = 1