Respuesta :
-(2.1) + (-5.9) + (-3.7) = -(2.1 + 5.9) + (-3.7) = -2.1 - (5.9 + 3.7) = -(2.1 + 5.9 + 3.7)
THerefore, options a, b and d are equivalent.
THerefore, options a, b and d are equivalent.