Jawapan

2014-07-04T21:46:12+08:00
 \frac{1}{n} -  \frac{n-4}{3n}

 \frac{3}{3n} -  \frac{n-4}{3n}                     ----------> Tukar pecahan agar penyebut jadi sama

 \frac{3-(n-4)}{3n}                     -----------> Gabungkan pecahan

 \frac{3-n+4}{3n}

 \frac{7-n}{3n}