Rút gọn biểu thức

7) (x + 1)²-(x-2)(x+2)
(2x-1)²-(x+5)(x-5)
8)
9) (x + 2)² + 2x-8
3
10) (2x - y) (x²-2x-²)
11) (2x-5)(3x+2)
12) x(x + 1) − x +5x