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受欢迎的代数 >

x^2-7.2x+12.8=0

解答

x^{2} - 7.2 x + 12.8 = 0

解答

x = 4, x = \frac{16}{5}

+1

十进制

x = 4, x = 3.2

求解步骤

x^{2} - 7.2 x + 12.8 = 0

在两边乘以

10

10 x^{2} - 72 x + 128 = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 72 ) \pm ( - 72 ) ^{2} - 4 \cdot 10 \cdot 128}{2 \cdot 10}

(- 72)^{2} - 4 \cdot 10 \cdot 128 = 8

x_{1, 2} = \frac{- ( - 72 ) \pm 8}{2 \cdot 10}

将解分隔开

x_{1} = \frac{- ( - 72 ) + 8}{2 \cdot 10}, x_{2} = \frac{- ( - 72 ) - 8}{2 \cdot 10}

x = \frac{- ( - 72 ) + 8}{2 \cdot 10} : 4

x = \frac{- ( - 72 ) - 8}{2 \cdot 10} : \frac{16}{5}

二次方程组的解是:

x = 4, x = \frac{16}{5}

作图

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5 x = (2 x + 1)^{2}

-4.9t^2+11t+500=0

- 4.9 t^{2} + 11 t + 500 = 0

completesquare-x^2-4x+5

co m pl e t es q u a re - x^{2} - 4 x + 5

4 x^{2} + 16 x - 87 = - 3

0 = 12 x^{2} - 72 x + 81