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 >

r^2+3r=1

解答

r^{2} + 3 r = 1

解答

r = \frac{- 3 + 13}{2}, r = \frac{- 3 - 13}{2}

+1

十进制

r = 0.30277 \dots, r = - 3.30277 \dots

求解步骤

r^{2} + 3 r = 1

将

1

para o lado esquerdo

r^{2} + 3 r - 1 = 0

使用求根公式求解

r_{1, 2} = \frac{- 3 \pm 3 ^{2} - 4 \cdot 1 \cdot ( - 1 )}{2 \cdot 1}

3^{2} - 4 \cdot 1 \cdot (- 1) = 13

r_{1, 2} = \frac{- 3 \pm 13}{2 \cdot 1}

将解分隔开

r_{1} = \frac{- 3 + 13}{2 \cdot 1}, r_{2} = \frac{- 3 - 13}{2 \cdot 1}

r = \frac{- 3 + 13}{2 \cdot 1} : \frac{- 3 + 13}{2}

r = \frac{- 3 - 13}{2 \cdot 1} : \frac{- 3 - 13}{2}

二次方程组的解是:

r = \frac{- 3 + 13}{2}, r = \frac{- 3 - 13}{2}

作图

流行的例子

completesquare-2x^2+4x

co m pl e t es q u a re - 2 x^{2} + 4 x

(3-x)^2=(1+2x)^2

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

- 6 x^{2} + 6 x + 12 = 0

x^{2} + 15 x + 16 = 0

solvefor x,x^2+2x-15=0

so l v e f or x, x^{2} + 2 x - 15 = 0