a+b= 14 a+c=21 calculeaza a+2b+c

Răspuns :

a + b = 14
a + c = 21
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a + 2b + c = ?

a = 21 - 14
a = 7

7 + b = 14
b = 14 - 7
b = 7

7 + c = 21
c = 21 - 7
c = 14

a + 2b + c = ?
7 + 2 × 7 + 14 = ?
7 + 14 + 14 = ?
21 + 14 = 35

Succes !