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1.Efectueaza calculul: 8a-3a+7a-13a.
2.Calculeaza 2(-a+2b-c)-3(-a-b-c)-(a-b-2c).
va rog mult


Răspuns :

a)8a-3a+7a-13a=
5a+7a-13a=
12a-13a=-a

b)2(-a+2b-c)-3(-a-b-c)-(a-b-2c)=
-2a+2b-2c+3a+3b+3c-a+b+2c=
-2a+3a-a+2b+3b+b-2c+3c+2c=
6b+3c=3(2b+c)