Question

trei pixuri si patru penare costa 34 de lei.Doua pixuri si 6 penare costa 46 de lei.Cat costa un pix si cat costa un penar?

Answer 1

3pix+4 pen=34 lei/x2
2 pix+6 pen=46 lei/x3

6pix+8 pen=68 lei
6pix+18 pen=138 lei
10 pen=138-68=70 lei
1 pen=70:10=7 lei
6pen+2pix=46
6x7+2pix=46
42+2pix=46
2pix=46-42=4 lei
1pix=2:2=1 lei

Answer 2

[tex]Metoda~I:\\ \left \{ {{3a+4b=34} \atop {2a+6b=46}} \right. \\ =\ \textgreater \ 3a+4b=34|(+3)=\ \textgreater \ 9a+12b=102\\ =\ \textgreater \ 2a+6b=46|(-2)=\ \textgreater \ -4a-12b=-92\\ 5a=10=\ \textgreater \ a=10:5=\ \textgreater \ a=2\\ 3*2+4b=34=\ \textgreater \ 6+4b=34=\ \textgreater \ 4b=34-6=\ \textgreater \ 4b=28=\ \textgreater \ b=7\\ Proba:3*2+4*7=34\\ 6+28=34\\ 34=34 \sqrt{} \\\\ 2*2+6*7=46\\ 4+42=46\\ 46=46 \sqrt{} [/tex]