`***`Lời giải`***`
Bài 4.
a)
`\frac{3x^2y-5}{2xy}+\frac{5-7x^2y}{2xy} `
`=\frac{3x^2y-5+5-7x^2y}{2xy} `
`=\frac{-4x^2y}{2xy} `
`=-2x `
d)
`\frac{x+1}{2x-2}+\frac{3}{x^2-1}`
`=\frac{x+1}{2(x-1)}+\frac{3}{(x-1)(x+1)}`
`=\frac{(x+1)^2}{2(x-1)(x+1)}+\frac{6}{2(x-1)(x+1)}`
`=\frac{(x+1)^2+6}{2(x-1)(x+1)}`
`=\frac{x^2+2x+1+6}{2(x-1)(x+1)}`
`=\frac{x^2+2x+7}{2(x^2-1)}`
`=\frac{x^2+2x+7}{2x^2-2}`
g)
`\frac{2x}{x^2-1}\frac{x+1}{4xy}`
`=\frac{2x(x+1)}{4xy(x-1)(x+1)}`
`=\frac{1}{2y(x-1)}`
`=\frac{1}{2xy-2y}`
i)
`\frac{x^2-2x+1}{x+1}:\frac{x^2-1}{3}`
`=\frac{(x-1)^2}{x+1}:\frac{(x-1)(x+1)}{3}`
`=\frac{(x-1)^2}{x+1}.\frac{3}{(x-1)(x+1)}`
`=\frac{3(x-1)}{(x+1)^2}`
`=\frac{3x-3}{x^2+2x+1}`
k)
không có đề
