a) M=2/5-4/3+7/2=6/15-20/15+7/2=-14/15+7/2=-28/30+105/30=77/30
b)N=2/3-5/3*3/2=2/3-15/6=4/6-15/6=-11/6
c)L=(-7/4+1/2)/(2/7+1/4)=
-7/4+2/4)/(8/28+7/28)=-5/4/13/28=5/4*28/13=140/52=35/13
d)P=-28/5/-21=588/5
2. a) 1/M=30/77
b) 11/6
3. a) M-N=77/30+11/6=77/30+55/30=132/30=22/5
b) N*L=-11/6*35/13=-385/78
c) M/N=77/30/-11/6=77/30*6/-11=462/-330=-7/5