870
а. х=3/5-1/8=24/40-5/40=19/40
б. х=5/12-1/3=5/12-4/12=1/12
в. х=1/5+3/20=4/20+3/20=7/20
г. х=4/21+3/7=4/21+9/21=13/21
д . х=4/5-1/6=24/30-5/30=19/30
е. х=5/8-1/3=15/24-8/24=7/24
871
а. =24/54-16/54=8/54=4/27
б. =21/48-10/48=11/48
в. =24/132-11/132=13/132
г. =24/26-15/26=9/26
д. =45/140-44/140=1/140
е. =273/280-190/280=83/280