Question

aflati suma nr a+bdaca a)a+2b=19 si 2a+b=23 b)3a+b=26si a+3b=34

Answer 1

a) a+2b=19
2a+b=23 adunam aceste 2 relatii si obtinem:
3a+3b=42
3(a+b)=42
a+b=14
b)3a+b=26
a+3b=34 facem acelasi lucru:
4a+4b=60
4(a+b)=60
a+b=15

Answer 2

a+2b=19
2a+b=23
_________ adunam cele doua relatii si rezulta
3a+3b=42 /:3  ( dam factor comun pe 3 )⇒a+b=14


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3a+b=26
a+3b=34
________
4a+4b=60 /:4 ( dam factor comun pe 4 )⇒a+b=15