Simplify each rational expression.
Original Expression Simplified Expression
12164x\displaystyle \frac{{{12}}}{{{16}-{4}{x}}}  
6x15x23x\displaystyle \frac{{{6}{x}}}{{{15}{x}^{{2}}-{3}{x}}}  
9x+327x+9\displaystyle \frac{{{9}{x}+{3}}}{{{27}{x}+{9}}}  
14x+67x+3\displaystyle \frac{{{14}{x}+{6}}}{{{7}{x}+{3}}}