Respuesta :
Subtracting means adding the opposite.Subtracting -5.1 means adding the opposite of -5.1 which is +5.1.
2.8 - (-5.1) = 2.8 + (+5.1) = 2.8 + 5.1 = 7.9
2.8 - (-5.1) = 2.8 + (+5.1) = 2.8 + 5.1 = 7.9