[tex]a+b=1[/tex]
[tex] \frac{2a}{5} = \frac{3b}{7} [/tex]
[tex]2a*7=5*3b[/tex]
[tex]14a=15b[/tex]
[tex]a= \frac{15b}{14} [/tex]
[tex]a+b=1[/tex]
[tex] \frac{15b}{14} +b=1[/tex]
[tex]15b+14b=14[/tex]
[tex]29b=14[/tex]
[tex]b= \frac{14}{29} [/tex]
[tex]a= \frac{15}{14} b= \frac{15}{14} * \frac{14}{29} = \frac{15}{29} [/tex]
Verificare:
[tex]a+b= \frac{15}{29} + \frac{14}{29} = \frac{29}{29} =1[/tex]