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受欢迎的代数 >

x^2=-7x-5

解答

x^{2} = - 7 x - 5

解答

x = \frac{- 7 + 29}{2}, x = \frac{- 7 - 29}{2}

+1

十进制

x = - 0.80741 \dots, x = - 6.19258 \dots

求解步骤

x^{2} = - 7 x - 5

将

5

para o lado esquerdo

x^{2} + 5 = - 7 x

将

7 x

para o lado esquerdo

x^{2} + 5 + 7 x = 0

改写成标准形式

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

x^{2} + 7 x + 5 = 0

使用求根公式求解

x_{1, 2} = \frac{- 7 \pm 7 ^{2} - 4 \cdot 1 \cdot 5}{2 \cdot 1}

7^{2} - 4 \cdot 1 \cdot 5 = 29

x_{1, 2} = \frac{- 7 \pm 29}{2 \cdot 1}

将解分隔开

x_{1} = \frac{- 7 + 29}{2 \cdot 1}, x_{2} = \frac{- 7 - 29}{2 \cdot 1}

x = \frac{- 7 + 29}{2 \cdot 1} : \frac{- 7 + 29}{2}

x = \frac{- 7 - 29}{2 \cdot 1} : \frac{- 7 - 29}{2}

二次方程组的解是:

x = \frac{- 7 + 29}{2}, x = \frac{- 7 - 29}{2}

作图

流行的例子

j(x)=-3x^2-18x-28

j (x) = - 3 x^{2} - 18 x - 28

x (x - 10) = - 25

-7/2 x^2+3x+8/3 =0

- \frac{7}{2} x^{2} + 3 x + \frac{8}{3} = 0

4 x^{2} + 3 x = 1

\frac{1}{4} r^{2} + 2 r + 3 = 0