Salutare!
[tex]\bf a+b=14\:\:\:|\cdot2\:\:\text{(\it inmultim toata relatia cu 2)}[/tex]
[tex]\bf 2a+2b=28[/tex] (relatia 1)
[tex]\bf b+c=9[/tex] (relatia 2)
Adunam cele doua relatii
[tex]\bf 2a+2b+ b+c=28+9[/tex]
[tex]\boxed{\bf 2a+3b+ c=37}[/tex]
Raspuns: [tex]\boxed{\bf 2a+3b+ c=37}[/tex]