zs

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

受欢迎的代数 >

1440=30x-0.1x^2

解答

1440 = 30 x - 0.1 x^{2}

解答

x = 60, x = 240

求解步骤

1440 = 30 x - 0.1 x^{2}

在两边乘以

10

14400 = 300 x - x^{2}

交换两边

300 x - x^{2} = 14400

将

14400

para o lado esquerdo

300 x - x^{2} - 14400 = 0

改写成标准形式

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

- x^{2} + 300 x - 14400 = 0

使用求根公式求解

x_{1, 2} = \frac{- 300 \pm 30 0 ^{2} - 4 ( - 1 ) ( - 14400 )}{2 ( - 1 )}

30 0^{2} - 4 (- 1) (- 14400) = 180

x_{1, 2} = \frac{- 300 \pm 180}{2 ( - 1 )}

将解分隔开

x_{1} = \frac{- 300 + 180}{2 ( - 1 )}, x_{2} = \frac{- 300 - 180}{2 ( - 1 )}

x = \frac{- 300 + 180}{2 ( - 1 )} : 60

x = \frac{- 300 - 180}{2 ( - 1 )} : 240

二次方程组的解是:

x = 60, x = 240

作图

流行的例子

100+50t-4.9t^2=0

100 + 50 t - 4.9 t^{2} = 0

quadraticformula x^2-4x=0

q u a d r a t i c f or m u l a x^{2} - 4 x = 0

x^{2} + 0.5 x + 1 = 0

5=2(x-2)(x+3)+(x-3)(x+3)

5 = 2 (x - 2) (x + 3) + (x - 3) (x + 3)

x (x - 11) = 3