Simplify: x2−7x+12x2−9\frac{x^2 - 7x + 12}{x^2 - 9}x2−9x2−7x+12.
x−4x+3\frac{x-4}{x+3}x+3x−4
x+4x−3\frac{x+4}{x-3}x−3x+4
x−3x+4\frac{x-3}{x+4}x+4x−3
x−4x−3\frac{x-4}{x-3}x−3x−4