pake cara yaah... tolong yah besok mau di kumpul

2.)a.)-3m+4n-6+7n-8m+10
-11m+11n+4
b.)15a+7b-5c+(-11a)-12b+13d
15a+7b-5c-11a-12b+13d
4a-5b-5c+13d
3.)a.)-3m+4n-6-(7n-8m+10)
-3m+4n-6-7n+8m-10
5m-3n-16
b.)15a+7b-5c-(-11a-12b+3d)
15a+7b-5c+11a+12b-13d
26a+19b-5c-13d