1. 9xy-4a^2xy 2. 8a^3x-27b^3x 3. (xy-ab)^2+(bx-ay)^2 Giúp mik vs mik cần gấp

`1)`

`9xy-4a^2xy`

`=` `xy(9-4a^2)`

`=` `xy[3^2-(2a)^2]`

`=` `xy(3+2a)(3-2a)`

`2)`

`8a^3x-27b^3x`

`=` `x(8a^3-27b^3)`

`=` `x[(2a)^2-(3b)^3]`

`=` `x(2a-3b)[(2a)^2+2a.3b+(3b)^2]`

`=` `x(2a-3b)(4a^2+6ab+9b^2)`

`3)`

`(xy-ab)^2-(bx-ay)^2`

`=` `(xy-ab+bx-ay)[xy-ab-(bx-ay)]`

`=` `(xy-ab+bx-ay)(xy-ab-bx+ay)`

`=` `[(xy+bx)+(-ab-ay)][(xy-bx)+(-ab+ay)]`

`=` `[x(y+b)-a(b+y)].[x(y-b)-a(b-y)]`

`=` `(b+y)(x-a)[(x(y-b)+a(y-b)]`

`=` `(b+y)(x-a)(y-b)(x+a)`