quadraticformula x^2+x-2=0

解答

x^{2} + x - 2 = 0

x = 1, x = - 2

求解步骤

x^{2} + x - 2 = 0

使用求根公式求解

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

1^{2} - 4 \cdot 1 \cdot (- 2) = 3

x_{1, 2} = \frac{- 1 \pm 3}{2 \cdot 1}

将解分隔开

x_{1} = \frac{- 1 + 3}{2 \cdot 1}, x_{2} = \frac{- 1 - 3}{2 \cdot 1}

x = \frac{- 1 + 3}{2 \cdot 1} : 1

x = \frac{- 1 - 3}{2 \cdot 1} : - 2

二次方程组的解是:

x = 1, x = - 2

- 6.5 x^{2} + 390 x - 2000 = 0

(- a + b + c - d) x^{2} + (a + 2 b + 2 c + (- d)) x + 2 d = 0

- 13 = 7 - 5 m^{2}

(2 x + 1)^{2} = 16

a x^{2} - c = 0