Răspuns:
5 st.ulei....2st.otet....43lei I·2
2st.ulei......5st.otet....34lei I·(-5)
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10 st.ulei.......4st.otet.........86lei
-10st.ulei......-25st.otet....-170lei
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/ -21o=-84=>o=84:21=>o=4 lei costa o sticla de otet
5u+2·4=43
5u=43-8
u=35:5=>u=7 lei o sticla de ulei
3 st.ulei+4st.otet=3·7+4·4=21+16=37 lei
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sau
aduni relatiile =>7u+7o=43+34
7(u+o)=77=>u+o=77:7=>u+o=11 lei costa o sticla de ulei+o sticla de otet
u=11-o
5u+2o=43
5(11-o)+2o=43
55-5o+2o=43
3o=55-43=>o=12:3=>o=4 lei st.de otet
5u+2·4=43
5u=43-8=>u=35:5=>7 lei o sticla de ulei
