Mong mn giúp em vs ạ em đang cần gắp lắm ạ

Đáp án:

 `63)`

$y^2-(x^2-2x+1)$

$= y^2-(x-1)^2$

$= (y-x+1).(y+x-1)$

`64)`

$4a^2-x^2-2x-1$

$= (2a)^2-(x^2+2x+1)$

$= (2a)^2-(x+1)^2$

$= (2a-x-1).(2a+x+1)$

`65)`

$25a^2b^2-4x^2+4x-1$

$= (5ab)^2-(4x^2-4x+1)$

$= (5ab)^2-(2x-1)^2$

$= (5ab-2x+1).(5ab+2x-1)$

`66)`

$36x^2-a^2+10a-25$

$= (6x)^2-(a^2-10a+25)$

$= (6x)^2-(a-5)^2$

$= (6x-a+5).(6x+a-5)$