Question

a)\(\dfrac{x+2}{x-2}-\dfrac{1}{x}=\dfrac{2}{x\left(x-2\right)}\)

b)2x+8=3x-15

Answer 1

`a) [ x + 2 ] / [ x - 2 ] - 1 / x = 2 / [x ( x - 2 )]`    `ĐK: x \ne 0,x \ne 2`

`<=> [ x ( x + 2 ) - ( x - 2 ) ] / [ x ( x - 2 ) ] = 2 / [ x ( x - 2 ) ]`

   `=> x^2 + 2x - x + 2 = 2`

`<=> x^2 + x = 0`

`<=> x ( x + 1 ) = 0`

`<=>` $\left[\begin{matrix} x = 0\\ x + 1 = 0\end{matrix}\right.$

`<=>` $\left[\begin{matrix} x = 0\text{ (ko t/m)}\\ x = -1\text{ (t/m)}\end{matrix}\right.$
Vậy `S = { -1}`

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`b) 2x + 8 = 3x - 15`

`<=> 3x - 2x = 8 + 15`

`<=> x = 23`

Vậy `S = { 23 }`

Answer 2

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