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受欢迎的代数 >

completesquare 2x^2+7x-3

解答

配方

2 x^{2} + 7 x - 3

解答

2 (x + \frac{7}{4})^{2} - \frac{73}{8}

求解步骤

2 x^{2} + 7 x - 3

将

2 x^{2} + 7 x - 3

改写为如下形式:

x^{2} + 2 a x + a^{2}

因式分解

2

2 (x^{2} + \frac{7 x}{2} - \frac{3}{2})

2 a = \frac{7}{2} : a = \frac{7}{4}

加和减

(\frac{7}{4})^{2}

2 (x^{2} + \frac{7 x}{2} - \frac{3}{2} + (\frac{7}{4})^{2} - (\frac{7}{4})^{2})

x^{2} + 2 a x + a^{2} = (x + a)^{2}

x^{2} + \frac{7}{2} x + (\frac{7}{4})^{2} = (x + \frac{7}{4})^{2}

2 ((x + \frac{7}{4})^{2} - \frac{3}{2} - (\frac{7}{4})^{2})

化简

2 (x + \frac{7}{4})^{2} - \frac{73}{8}

作图

流行的例子

a^{2} - 4 = 3 a

(6x^2+2x)/3 =20x

\frac{6 x ^{2} + 2 x}{3} = 20 x

x^{2} - 9 x = - 29

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

2 x^{2} + 4 x + 30 = 0