Đáp án `+` Giải thích các bước giải `!`
`(y)/(xy-5x^2)+(25x-15y)/(y^2-25x^2)`
`= (y)/(x(y-5x))+(25x-15y)/((y-5x)(y+5x))`
`= (y(y+5x))/(x(y-5x)(y+5x))+(x(25x-15y))/((x(y-5x)(y+5x))`
`= (y^2+5xy+25x^2-15xy)/(x(y-5x)(y+5x))`
`= (y^2-10xy+25x^2)/(x(y-5x)(y+5x))`
`= ((y-5x)^2)/(x(y-5x)(y+5x))`
`= (y-5x)/(x(y+5x))`