Toán Lớp 8: Rút gọn mỗi biểu thức sau:
x/x-1-x+1/x
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Toán Lớp 8: Rút gọn mỗi biểu thức sau:
x/x-1-x+1/x
Cần giải gấp ạ
Vote 5 saoooo
Comments ( 2 )
$\dfrac{x}{x-1}-\dfrac{x+1}{x}$ $;$ ĐK $(x≠0;x≠1)$
$=\dfrac{x^2}{x\left(x-1\right)}-\dfrac{\left(x+1\right)\left(x-1\right)}{x\left(x-1\right)}$
$=\dfrac{x^2-\left(x+1\right)\left(x-1\right)}{x\left(x-1\right)}$
$=\dfrac{1}{x\left(x-1\right)}$
=1/(x – 1) – 1/x
=1/(x^2 – x)
$\dfrac{x}{x-1}$ – $\dfrac{x+1}{x}$
= $\dfrac{x.x}{x.(x-1)}$ – $\dfrac{(x+1)(x-1)}{x.(x-1)}$
= $\dfrac{x²}{x(x-1)}$ – $\dfrac{x² – 1}{x.(x – 1)}$
= $\dfrac{x² – x² + 1}{x.(x-1)}$
= $\dfrac{ 1}{x.(x-1)}$