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Stiind ca{a+b=25 a-b=5 ,afla a=? b=? prin metoda figurativa

Răspuns :

b|-----------|
a|-----------|+5
25-5=20
20:2=10(b)
a=10+5=15
[tex] \left \{ {{a+b=25} \atop {a-b=5}} \right. \ \textless \ =\ \textgreater \ \left \{ {{b=25-a} \atop {a-25+a=5}} \right. \ \textless \ =\ \textgreater \ \left \{ {{b=25-a} \atop {2a=30}} \right. \ \textless \ =\ \textgreater \ \left \{ {{a=15} \atop {b=25-15}} \right. \ \textless \ =\ \textgreater \ \left \{ {{a=15} \atop {b=10}} \right. [/tex]