Advertisements (Quảng cáo)
Tính
\({\rm{a)}}{{ – 1} \over {39}} + {{ – 1} \over {52}}\) \(b){{ – 6} \over 9} + {{ – 12} \over {16}}\)
\(c){{ – 2} \over 5} – {{ – 3} \over {11}}\) \({\rm{d)}}{{ – 34} \over {37}}.{{74} \over { – 85}}\)
\({\rm{e)}}{{ – 5} \over 9}:{{ – 7} \over {18}}\)
\({\rm{a)}}{{ – 1} \over {39}} + {{ – 1} \over {52}} = {{ – 4} \over {156}} + {{ – 3} \over {156}} = {{ – 7} \over {156}}\)
Advertisements (Quảng cáo)
\(b){{ – 6} \over 9} + {{ – 12} \over {16}} = {{ – 2} \over 3} + {{ – 3} \over 4} = {{ – 8} \over {12}} + {{ – 9} \over {12}} = {{ – 17} \over {12}}\)
\(c){{ – 2} \over 5} – {{ – 3} \over {11}} = {{ – 22} \over {55}} – {{ – 15} \over {55}} = {{ – 7} \over {55}}\)
\({\rm{d)}}{{ – 34} \over {37}}.{{74} \over { – 85}} = {{ – 17.2.37.2} \over {37.( – 17).5}} = {4 \over 5}\)
\({\rm{e)}}{{ – 5} \over 9}:{{ – 7} \over {18}} = {{ – 5} \over 9}.{{ – 18} \over 7} = {{10} \over 7}\)