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受欢迎的代数 >

3r^2=6r+5

解答

3 r^{2} = 6 r + 5

解答

r = \frac{3 + 2 6}{3}, r = \frac{3 - 2 6}{3}

+1

十进制

r = 2.63299 \dots, r = - 0.63299 \dots

求解步骤

3 r^{2} = 6 r + 5

将

5

para o lado esquerdo

3 r^{2} - 5 = 6 r

将

6 r

para o lado esquerdo

3 r^{2} - 5 - 6 r = 0

改写成标准形式

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

3 r^{2} - 6 r - 5 = 0

使用求根公式求解

r_{1, 2} = \frac{- ( - 6 ) \pm ( - 6 ) ^{2} - 4 \cdot 3 ( - 5 )}{2 \cdot 3}

(- 6)^{2} - 4 \cdot 3 (- 5) = 46

r_{1, 2} = \frac{- ( - 6 ) \pm 4 6}{2 \cdot 3}

将解分隔开

r_{1} = \frac{- ( - 6 ) + 4 6}{2 \cdot 3}, r_{2} = \frac{- ( - 6 ) - 4 6}{2 \cdot 3}

r = \frac{- ( - 6 ) + 4 6}{2 \cdot 3} : \frac{3 + 2 6}{3}

r = \frac{- ( - 6 ) - 4 6}{2 \cdot 3} : \frac{3 - 2 6}{3}

二次方程组的解是:

r = \frac{3 + 2 6}{3}, r = \frac{3 - 2 6}{3}

作图

流行的例子

(x - 3) (x - 1) = 8

5 x^{2} = 17

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