Respuesta :
A = 2ab + 2ac + 2bc
A = 2b(a + c) + 2ac
2b(a + c) = A - 2ac
b = (A - 2ac) / [2(a + c)]
A = 2b(a + c) + 2ac
2b(a + c) = A - 2ac
b = (A - 2ac) / [2(a + c)]
take b as a common factor
s=b (2a + 2c) +2 ac
s-2ac=b (2a+2c)
b=(s-2ac)/(2a+2c)
s=b (2a + 2c) +2 ac
s-2ac=b (2a+2c)
b=(s-2ac)/(2a+2c)