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受欢迎的代数 >

-2.5x^2+12x+21=0

解答

- 2.5 x^{2} + 12 x + 21 = 0

解答

x = - \frac{- 12 + 354}{5}, x = \frac{12 + 354}{5}

+1

十进制

x = - 1.36297 \dots, x = 6.16297 \dots

求解步骤

- 2.5 x^{2} + 12 x + 21 = 0

在两边乘以

10

- 25 x^{2} + 120 x + 210 = 0

使用求根公式求解

x_{1, 2} = \frac{- 120 \pm 12 0 ^{2} - 4 ( - 25 ) \cdot 210}{2 ( - 25 )}

12 0^{2} - 4 (- 25) \cdot 210 = 10354

x_{1, 2} = \frac{- 120 \pm 10 354}{2 ( - 25 )}

将解分隔开

x_{1} = \frac{- 120 + 10 354}{2 ( - 25 )}, x_{2} = \frac{- 120 - 10 354}{2 ( - 25 )}

x = \frac{- 120 + 10 354}{2 ( - 25 )} : - \frac{- 12 + 354}{5}

x = \frac{- 120 - 10 354}{2 ( - 25 )} : \frac{12 + 354}{5}

二次方程组的解是:

x = - \frac{- 12 + 354}{5}, x = \frac{12 + 354}{5}

作图

流行的例子

x^{2} + 4 x - 5 \geq 0

-(6-2x)=4(x+1)-2x-10

- (6 - 2 x) = 4 (x + 1) - 2 x - 10

化简 (2-5i)/i

s im pl i f y \frac{2 - 5 i}{i}

∣ b ∣ < 3

因式分解 xy^4+x^2y

f a c t or x y^{4} + x^{2} y