$\text { Đáp án: }$ ` x² ‐ x – xy – 2y² + 2y ` ` = –2y² + xy – 2xy + x² + 2y – x ` ` = –y(2y – x) – x(2y + x) + (2y – x) ` ` = (1 – y – x)(2y – x) ` Bình luận
`x^2-x-xy-2y^2+2y `
`⇔2y-x-2y^2+xy-2xy+x^2`
`⇔(2y-x)-y(2y-x)-x(2y-x)`
`⇔(2y-x)(1-y-x)`
$\text { Đáp án: }$
` x² ‐ x – xy – 2y² + 2y `
` = –2y² + xy – 2xy + x² + 2y – x `
` = –y(2y – x) – x(2y + x) + (2y – x) `
` = (1 – y – x)(2y – x) `