Jawabanmu

2014-09-03T20:51:14+07:00
42n+35m+7+50m+20n-9
42n+20n+35m+50m+7-9
62n+85m-2
2014-09-03T20:53:18+07:00
(42n+35m+7)-(50m-20n+9)
=42n+35m+7-50m+20n-9
=42n+20n+35m-50m+7-9
=62n-15m-2