Jawabanmu

2014-08-22T19:35:12+07:00
(42n+35m)-(50m-20n+9) = 42n+35m-50m+20n+9 = 62n-15m+9
2014-08-22T19:35:22+07:00
= (42n + 35m) - (50m - 20n + 9)
= (42n + 35m) - 50m + 20n - 9
= 62n - 15m -9 <~ Jawaban