a+b=-7
b+c=-10
2a+5b+3c=?


Răspuns :

A+b=-7

b+c=-10

2a+5b+3c= 2a+2b + 3b+3c = 2(a+b) + 3(b+c) = 2*(-7)+3*(-10)= -14 -30 =- 44