Đáp án + Giải thích các bước giải:
`P =(3x^2 − 2xy − y^2)/(2x^2 + xy − y^2) : (3x^2 − 4xy + y^2)/(3x^2 + 2xy − y^2)`
`=(3x^2 − 2xy − y^2)/(2x^2 + xy − y^2) . (3x^2 + 2xy − y^2)/(3x^2 − 4xy + y^2)`
`= (3x^2 − 3xy+xy − y^2)/(2x^2 + 2xy-xy − y^2) . (3x^2 + 3xy-xy − y^2)/(3x^2 − 3xy-xy + y^2)`
`= (3x(x-y) +y(x-y))/(2x(x+y)-y(x+y)) . (3x(x+y)-y (x+y))/(3x(x-y)-y(x-y))`
`= ((x-y)(3x+y))/((x+y)(2x-y)) . ((x+y)(3x-y))/((x-y)(3x-y))`
`= ((x-y)(3x+y)(x+y)(3x-y))/((x-y)(3x-y)(x+y)(2x-y))`
`= (3x+y)/(2x-y)`
`Vậy` `P ` `= (3x+y)/(2x-y)`
