Question

a+2b+3C=330 a+c=70 a+b+2c=?

Answer 1

a + 2 b + 3 c = 330  si a + c = 70 

a + c + 2 b + 2 c = 330 
( a + c) + 2 ( b + c ) = 330 
70 + 2 ( b + c ) = 330 
2 ( b + c ) = 330 - 70 
b + c = 260 : 2 
b + c = 130 

a + b + 2 c = ( a + c ) + ( b + c ) = 70 + 130 = 200  
           2 c = c + c 

Answer 2

a+2b+c =330
a+c=70

a+2b+3c=330
il descompunem pe  3c=c+2c
a+2b+c+2c=330
a+c+2b+2c= 330
70 +2b+2c=330
2b+2c=330-70
2(b+c) =260
impartim toata relatia cu 2
b+c= 130

a+b+2c= a+b+ c+c= a+c +b+c= 70+ 130=200