3p-7+p=13 ok so you will want to add 3p to 1p if there's only a variable then there a invisible 1 in front of it so you'll add 3 to 1 wich is 4 so now your problem Is now 4p-7=13 you then make the negative 7 to a positive 7 so now your going to add 13+7 wich equals 20 now you divide 20 by 4 wich gives you 5