Giúp emm với ạaa e cần gấpp

Đáp án+Giải thích các bước giải:

9) `169 - a^2 + 2ab - b^2`

`= 169 - (a^2 - 2ab + b^2)`

`= 13^2 - (a - b)^2`

`= (13 - a + b)(13 + a - b)`

10) `a^2+ 6a - 4b^2 + 9`

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

`= (a + 3)^2 - (2b)^2`

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

11) `4x - 4 + 9y^2 - x^2`

`= 9y^2 - (x^2 - 4x + 4)`

`= (3y)^2 - (x - 2)^2`

`= (3y - x + 2)(3y + x - 2)`

12) `5x^2 - 10x + 5 - 45t^2`

`= 5(x^2 - 2x + 1 - 9t^2)`

`= 5[(x-1)^2 - (3t)^2]`

`= 5(x-1-3t)(x-1+3t)`

13) `x^2 - 36y^2t^2 - 10x + 25`

`= (x^2 - 10x + 25) - 36y^2t^2`

`= (x - 5)^2 - (6yt)^2`

`= (x - 5 - 6yt)(x - 5 + 6yt)`

14) `9x^2 - 16y^2 + 6x + 1`

`= (9x^2 + 6x + 1) - 16y^2`

`= (3x + 1)^2 - (4y)^2`

`= (3x + 1 - 4y)(3x + 1 + 4y)`

15) `x^2 - 2xy + y^2 - 16z^2`

`= (x - y)^2 - (4z)^2`

`= (x - y - 4z)(x - y + 4z)`

16) `x^2 - y^2 + 14x + 49`

`= (x^2 + 14x + 49) - y^2`

`= (x + 7)^2 - y^2`

`= (x + 7 - y)(x + 7 + y)`

`\ttcolor{red}{#ILy}`