Respuesta:
(-11-4-6)-[-(+6-2-3)-(-7)+(4-5)]
-21-[-6-2-3)+7(+4-5)]
-21-[-11+7-1]
-21-[-12+7]
-21[+12+7]
-21+19
-2
(-21) -(-1+7+(-1))
-21-(-1+7-1)
-21-5
-26
