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受欢迎的代数 >

x^{-2}-8x^{-1}+15=0

解答

x^{- 2} - 8 x^{- 1} + 15 = 0

解答

x = \frac{1}{3}, x = \frac{1}{5}

+1

十进制

x = 0.33333 \dots, x = 0.2

求解步骤

x^{- 2} - 8 x^{- 1} + 15 = 0

整理后得

\frac{1}{x ^{2}} - \frac{8}{x} + 15 = 0

乘以最小公倍数

1 - 8 x + 15 x^{2} = 0

解

1 - 8 x + 15 x^{2} = 0 : x = \frac{1}{3}, x = \frac{1}{5}

x = \frac{1}{3}, x = \frac{1}{5}

验证解

找到无定义的点（奇点）:

x = 0

将不在定义域的点与解相综合:

x = \frac{1}{3}, x = \frac{1}{5}

作图

流行的例子

\frac{4}{5 x + 8} = - 24

5/(3t)=3-(6/(15t))

\frac{5}{3 t} = 3 - (\frac{6}{15 t})

\frac{1}{x} + \frac{1}{3 x} = 12

x^{-2}+9x^{-1}-10=0

x^{- 2} + 9 x^{- 1} - 10 = 0

solvefor x,y=(x-1)/(x+3)

so l v e f or x, y = \frac{x - 1}{x + 3}