`1)`

`(x+2)^2 - 3(x - 1) = 9`

`=> x^2 + 4x + 4 - 3x + 3 = 9`

`=> x^2 + x + 7 = 9`

`=> x^2 + x - 2 = 0`

`=> (x - 1)(x + 2) = 0`

`=> x \in {1 ; -2}`

Vậy `x \in{1;-2}`

`2)`

`(x + 1)^2 + 3(-x + 2) = 9`

`=> x^2 + 2x + 1 - 3x + 6 = 9`

`=> x^2 - x + 7 = 9`

`=> x^2 - x - 2 = 0`

`=> (x - 2)(x + 1) = 0`

`=> x \in {-1 ; 2}`

Vậy `x \in {-1 ; 2}`

`3)`

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

`=> 4x^2 - 4x + 1 - x^2 - 2x - 1 = -3`

`=> 3x^2 - 6x + 3 = 0`

`=> x^2 - 2x + 1 = 0`

`=> (x - 1)^2 = 0`

`=> x = 1`

Vậy `x = 1`

`4)`

`2(x - 2)^2 - (x - 1)(x + 1) = 2`

`=> 2x^2 - 8x + 8 - x^2 + 1 = 2`

`=> x^2 - 8x + 7 = 0`

`=> (x - 7)(x - 1) = 0`

`=> x \in {1 ; 7}`
Vậy `x \in {1;7}`

`5)`

`(x - 2)(x + 2) - 5(4-x) = 12`

`=> x^2 - 4 - 20 + 5x = 12`

`=> x^2 + 5x - 24 = 12`

`=> x^2 + 5x -36 =0`

`=> (x -4)(x+9) = 0`

`=> x \in {4 ; -9}`

Vậy `x \in {4;-9}`

`6)`

`(x + 3)(2x - 1) - (x - 3)^2 = 30`

`=> 2x^2 + 5x - 3 - x^2 + 6x - 9 = 30`

`=> x^2 + 11x - 12 = 30`

`=> x^2 + 11x - 42 = 0`

`=> (x - 3)(x+ 14) = 0`

`=> x \in { 3 ; -14}`

Vậy `x \in { 3;-14}`