Giúp tui ik cảm ơn nhìu nha

`b,`

`\frac{-3x^2}{2y}`

`=\frac{-3x^2 .(-1)}{2y.(-1)}`

`=\frac{3x^2}{-2y}`

`->VP(đpcm)`

$\\$
`c,`

`\frac{2.(x-y)}{3.(y-x)}`

`=\frac{-2.(y-x)}{3.(y-x)}`

`=\frac{-2.\cancel{(y-x)}}{3.\cancel{(y-x)}}`

`=\frac{-2}{3}`

`->VP(đpcm)`