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受欢迎的代数 >

(3x-9)^2=5x+7

解答

(3 x - 9)^{2} = 5 x + 7

解答

x = \frac{59 + 817}{18}, x = \frac{59 - 817}{18}

+1

十进制

x = 4.86573 \dots, x = 1.68982 \dots

求解步骤

(3 x - 9)^{2} = 5 x + 7

展开

(3 x - 9)^{2} : 9 x^{2} - 54 x + 81

9 x^{2} - 54 x + 81 = 5 x + 7

将

7

para o lado esquerdo

9 x^{2} - 54 x + 74 = 5 x

将

5 x

para o lado esquerdo

9 x^{2} - 59 x + 74 = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 59 ) \pm ( - 59 ) ^{2} - 4 \cdot 9 \cdot 74}{2 \cdot 9}

(- 59)^{2} - 4 \cdot 9 \cdot 74 = 817

x_{1, 2} = \frac{- ( - 59 ) \pm 817}{2 \cdot 9}

将解分隔开

x_{1} = \frac{- ( - 59 ) + 817}{2 \cdot 9}, x_{2} = \frac{- ( - 59 ) - 817}{2 \cdot 9}

x = \frac{- ( - 59 ) + 817}{2 \cdot 9} : \frac{59 + 817}{18}

x = \frac{- ( - 59 ) - 817}{2 \cdot 9} : \frac{59 - 817}{18}

二次方程组的解是:

x = \frac{59 + 817}{18}, x = \frac{59 - 817}{18}

作图

流行的例子

c^{2} - 5 c + 9 = 0

y (y - 13) + 6 y = 18

7(x+5)(x-3)-5(x+3)(x-3)=0

7 (x + 5) (x - 3) - 5 (x + 3) (x - 3) = 0

2x^2+20x+15=127

2 x^{2} + 20 x + 15 = 127

6x^2-46x+312=14x

6 x^{2} - 46 x + 312 = 14 x