Question

Calculați 3a+5b+4c+1,daca a+b=12 si b+2c=7

Answer 1

a+b=12 /*3
3a+3b=36
b+2c=7 /*2
2b+4c=14     +
___________
3a+3b+2b+4c=36+14
3a+5b+4c+1=50+1=51

Answer 2

[tex] + \eft \{ {{a+b=12 \\ | (*3) } \atop {b+2c=7 (*2) }} \right. \\ \\ 3a+5b+4c+1 =36+14 +1=50 +1 =51 [/tex]