[tex]y = log_{3}( \frac{x + 3}{4 - x} ) \\ \frac{x + 3}{4 - x} > 0 \\ \frac{x + 3}{x - 4} < 0 \\ (x + 3)(x - 4) < 0 \\ + + + ( - 3) - - - (4) + + + \\ x \: \epsilon\: ( - 3; \: 4)[/tex]