2x^2+8x-11=0

解答

2 x^{2} + 8 x - 11 = 0

x = \frac{- 4 + 38}{2}, x = - \frac{4 + 38}{2}

十进制

x = 1.08220 \dots, x = - 5.08220 \dots

求解步骤

2 x^{2} + 8 x - 11 = 0

使用求根公式求解

x_{1, 2} = \frac{- 8 \pm 8 ^{2} - 4 \cdot 2 ( - 11 )}{2 \cdot 2}

8^{2} - 4 \cdot 2 (- 11) = 238

x_{1, 2} = \frac{- 8 \pm 2 38}{2 \cdot 2}

将解分隔开

x_{1} = \frac{- 8 + 2 38}{2 \cdot 2}, x_{2} = \frac{- 8 - 2 38}{2 \cdot 2}

x = \frac{- 8 + 2 38}{2 \cdot 2} : \frac{- 4 + 38}{2}

x = \frac{- 8 - 2 38}{2 \cdot 2} : - \frac{4 + 38}{2}

二次方程组的解是:

x = \frac{- 4 + 38}{2}, x = - \frac{4 + 38}{2}

\frac{1}{3} (u - \frac{3}{2}) (u + \frac{3}{2}) = u (\frac{u}{3} \frac{1}{4})

co m pl e t es q u a re 2 x^{2} - 10 x = 0

x - 3 - (- x (x + 1) + 4) - 5 = (- x + 6)

co m pl e t es q u a re 2 x^{2} - x + 6

(2 x + 3)^{2} = 1