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受欢迎的代数 >

4x^2+45=-28x

解答

4 x^{2} + 45 = - 28 x

解答

x = - \frac{5}{2}, x = - \frac{9}{2}

+1

十进制

x = - 2.5, x = - 4.5

求解步骤

4 x^{2} + 45 = - 28 x

将

28 x

para o lado esquerdo

4 x^{2} + 45 + 28 x = 0

改写成标准形式

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

4 x^{2} + 28 x + 45 = 0

使用求根公式求解

x_{1, 2} = \frac{- 28 \pm 2 8 ^{2} - 4 \cdot 4 \cdot 45}{2 \cdot 4}

2 8^{2} - 4 \cdot 4 \cdot 45 = 8

x_{1, 2} = \frac{- 28 \pm 8}{2 \cdot 4}

将解分隔开

x_{1} = \frac{- 28 + 8}{2 \cdot 4}, x_{2} = \frac{- 28 - 8}{2 \cdot 4}

x = \frac{- 28 + 8}{2 \cdot 4} : - \frac{5}{2}

x = \frac{- 28 - 8}{2 \cdot 4} : - \frac{9}{2}

二次方程组的解是:

x = - \frac{5}{2}, x = - \frac{9}{2}

作图

流行的例子

因式分解 x^2-x-2=0

f a c t or x^{2} - x - 2 = 0

- x^{2} + 8 x + 20 = 0

x^{2} + 18 x - 27 = 0

2 x^{2} - 36 = 0

solvefor x,f=2x^2-3y-4

so l v e f or x, f = 2 x^{2} - 3 y - 4