Dacă a+B =20,3si B +c =23,14atunci a+2xb+c =?

Răspuns :

A+b=20,3
B+c=23,14
=> Adunam cele doua expresii:
--------------------
(+)
<=>a+2b+c=43,44

Succes in continuare !

a=20,3-b, c=23,14-b, inlocuim a si c

20,3-b+2b+23,14-b=20,3+23,14=43,44