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受欢迎的代数 >

x^2-7x-20=0

解答

x^{2} - 7 x - 20 = 0

解答

x = \frac{7 + 129}{2}, x = \frac{7 - 129}{2}

+1

十进制

x = 9.17890 \dots, x = - 2.17890 \dots

求解步骤

x^{2} - 7 x - 20 = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 7 ) \pm ( - 7 ) ^{2} - 4 \cdot 1 \cdot ( - 20 )}{2 \cdot 1}

(- 7)^{2} - 4 \cdot 1 \cdot (- 20) = 129

x_{1, 2} = \frac{- ( - 7 ) \pm 129}{2 \cdot 1}

将解分隔开

x_{1} = \frac{- ( - 7 ) + 129}{2 \cdot 1}, x_{2} = \frac{- ( - 7 ) - 129}{2 \cdot 1}

x = \frac{- ( - 7 ) + 129}{2 \cdot 1} : \frac{7 + 129}{2}

x = \frac{- ( - 7 ) - 129}{2 \cdot 1} : \frac{7 - 129}{2}

二次方程组的解是:

x = \frac{7 + 129}{2}, x = \frac{7 - 129}{2}

作图

流行的例子

2 x + 2 = x + 11

3(x-2)-5(2x-1)-2(3x+4)+10=0

3 (x - 2) - 5 (2 x - 1) - 2 (3 x + 4) + 10 = 0

2 x = 2

s im pl i f y 3 - (\frac{1}{2})

因式分解 p^6q^4-q^7

f a c t or p^{6} q^{4} - q^{7}