Respuesta :

Answer:

a = 3

Step-by-step explanation:

Step-by-step explanation:

2a + 2b + 2c

= (a + b) + (b + c) + (c + a)

= 5 + 6 + 7

= 18.

Hence, a + b + c = 9 and a = (a + b + c) - (b + c) = 9 - 6 = 3.