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受欢迎的代数 >

1-0.9x+0.2x^2=0

解答

1 - 0.9 x + 0.2 x^{2} = 0

解答

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

+1

十进制

x = 2.5, x = 2

求解步骤

1 - 0.9 x + 0.2 x^{2} = 0

在两边乘以

10

10 - 9 x + 2 x^{2} = 0

改写成标准形式

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

2 x^{2} - 9 x + 10 = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 9 ) \pm ( - 9 ) ^{2} - 4 \cdot 2 \cdot 10}{2 \cdot 2}

(- 9)^{2} - 4 \cdot 2 \cdot 10 = 1

x_{1, 2} = \frac{- ( - 9 ) \pm 1}{2 \cdot 2}

将解分隔开

x_{1} = \frac{- ( - 9 ) + 1}{2 \cdot 2}, x_{2} = \frac{- ( - 9 ) - 1}{2 \cdot 2}

x = \frac{- ( - 9 ) + 1}{2 \cdot 2} : \frac{5}{2}

x = \frac{- ( - 9 ) - 1}{2 \cdot 2} : 2

二次方程组的解是:

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

作图

流行的例子

5x^2-7x+6=10x-7x^2

5 x^{2} - 7 x + 6 = 10 x - 7 x^{2}

100+(n-2)^2=149

100 + (n - 2)^{2} = 149

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

solvefor x,x^2+y^2+z^2=4z

so l v e f or x, x^{2} + y^{2} + z^{2} = 4 z

6 x^{2} - 7 x + 2 = 7