

Rút gọn biểu thức
1) x +3 + [math]\sqrt{x^2 - 6x + 9}[/math] (x ≤ 3)
2) [math]\sqrt{x^2 + 4x + 4}[/math] - [math]\sqrt{x^2}[/math] (-2 ≤ x ≤ 0)3) [math]\sqrt{x^2 + 2\sqrt{x^2 - 1}}[/math] - [math]\sqrt{x^2 - 2\sqrt{x^2 - 1}}[/math]4) [math]\frac{\sqrt{x^2 - 2x + 1}}{x - 1}[/math] (x > 1)
5) |x - 2| + [math]\frac{\sqrt{x^2 - 4x + 4}}{x - 2}[/math] (x < 2)
6) 2x - 1 - [math]\frac{\sqrt{x^2 - 10x + 25}}{x - 5}[/math]