Simplify: x2−16x2+7x+12\frac{x^2 - 16}{x^2 + 7x + 12}x2+7x+12x2−16.
x−4x+3\frac{x-4}{x+3}x+3x−4
x+4x+3\frac{x+4}{x+3}x+3x+4
x−4x−3\frac{x-4}{x-3}x−3x−4
x−4x+4\frac{x-4}{x+4}x+4x−4