Resposta :
2a/2a+b = -2
2a - 2 (2a+b)/2a+b
2a - 4a - 2b/2ab
simplificando por 2
a - 2a - b/2ab =
-a - b/2ab
2a - 2 (2a+b)/2a+b
2a - 4a - 2b/2ab
simplificando por 2
a - 2a - b/2ab =
-a - b/2ab