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受欢迎的代数 >

3x^2+4x^2=6x+9

解答

3 x^{2} + 4 x^{2} = 6 x + 9

解答

x = \frac{3 ( 1 + 2 2 )}{7}, x = \frac{3 ( 1 - 2 2 )}{7}

+1

十进制

x = 1.64075 \dots, x = - 0.78361 \dots

求解步骤

3 x^{2} + 4 x^{2} = 6 x + 9

整理后得

7 x^{2} = 6 x + 9

将

9

para o lado esquerdo

7 x^{2} - 9 = 6 x

将

6 x

para o lado esquerdo

7 x^{2} - 9 - 6 x = 0

改写成标准形式

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

7 x^{2} - 6 x - 9 = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 6 ) \pm ( - 6 ) ^{2} - 4 \cdot 7 ( - 9 )}{2 \cdot 7}

(- 6)^{2} - 4 \cdot 7 (- 9) = 122

x_{1, 2} = \frac{- ( - 6 ) \pm 12 2}{2 \cdot 7}

将解分隔开

x_{1} = \frac{- ( - 6 ) + 12 2}{2 \cdot 7}, x_{2} = \frac{- ( - 6 ) - 12 2}{2 \cdot 7}

x = \frac{- ( - 6 ) + 12 2}{2 \cdot 7} : \frac{3 ( 1 + 2 2 )}{7}

x = \frac{- ( - 6 ) - 12 2}{2 \cdot 7} : \frac{3 ( 1 - 2 2 )}{7}

二次方程组的解是:

x = \frac{3 ( 1 + 2 2 )}{7}, x = \frac{3 ( 1 - 2 2 )}{7}

作图

流行的例子

solvefor x,(x-2)^2+((x+3)-4)^2=25

so l v e f or x, (x - 2)^{2} + ((x + 3) - 4)^{2} = 25

a^{2} + 7^{2} = 1 0^{2}

(x)=5x^2-900x+1200000

(x) = 5 x^{2} - 900 x + 1200000

10 x^{2} = 18 x

3 X^{2} + 9 X - 2 = 0