$\frac{x^2 - 9}{x^2 + 6x + 8} + \frac{x - 3}{x + 2} = $

$\frac{x - 3}{x^2 - 9} + \frac{x + 7}{x^2 + 10x + 21} = $

$\frac{5x^2 - 15x}{x^2 - 5x + 6} + \frac{x}{x - 2} = $