6.a)64/14+(7*41/84-46*4/84)=64*6/14+103/84=(384+103)/84=487/84=5 67/84
б) 89/12-(13/8+49/24)=89/12-(13*3/8+49/24)=89/12-88/12=1/12.
в)79/12+(203/40-68/15)=79/12+(203*3/120-68*24/120)=79/12-1023/120=79*10/120-1023/120=790-1023/120=-233/120
7.а) 42/56=7*6/7*8=6/8=3/4
б)150/45=15*10/15*3=10/3=3 1/3
в)84/63=7*12/7*9=12/9=4/3=1 1/3
г) 176ab/242bc=2*44ab/2*121bc=44a/121c