e compran 30 libros a S/ 720, si se pierden 10 libros, ¿a cuánto debo vender cada uno de los restantes para ganar un total de S/180?

Which of the following questions describes the equation g + (-4) = -5? a)what number, when added to negative four, is equal to negative five? b)what number, when added to negative five, is equal to negative four? c)what number, when subtracted from negative four, is equal to negative five? d)what number, when subtracted from negative five, is equal to negative four?