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受欢迎的代数 >

(2x^2-7x)^2+2x^2-7x=20

解答

(2 x^{2} - 7 x)^{2} + 2 x^{2} - 7 x = 20

解答

x = 1, x = 4, x = - \frac{1}{2}, x = \frac{5}{2}

+1

十进制

x = 1, x = 4, x = - 0.5, x = 2.5

求解步骤

(2 x^{2} - 7 x)^{2} + 2 x^{2} - 7 x = 20

展开

(2 x^{2} - 7 x)^{2} + 2 x^{2} - 7 x : 4 x^{4} - 28 x^{3} + 51 x^{2} - 7 x

4 x^{4} - 28 x^{3} + 51 x^{2} - 7 x = 20

将

20

para o lado esquerdo

4 x^{4} - 28 x^{3} + 51 x^{2} - 7 x - 20 = 0

因式分解

4 x^{4} - 28 x^{3} + 51 x^{2} - 7 x - 20 : (x - 1) (x - 4) (2 x + 1) (2 x - 5)

(x - 1) (x - 4) (2 x + 1) (2 x - 5) = 0

使用零因数法则： If

ab = 0

then

a = 0

or

b = 0

x - 1 = 0 or x - 4 = 0 or 2 x + 1 = 0 or 2 x - 5 = 0

解

x - 1 = 0 : x = 1

解

x - 4 = 0 : x = 4

解

2 x + 1 = 0 : x = - \frac{1}{2}

解

2 x - 5 = 0 : x = \frac{5}{2}

解为

x = 1, x = 4, x = - \frac{1}{2}, x = \frac{5}{2}

作图

流行的例子

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