Okay so obviously you are wanting to get d by itself so how to do that is to get everything on the left side( the side your variable is on) to the other side. Now how you do that is you simply subtract or add from that side and then again to the other side ( whats past the equal sign) so you take 700 and your going to wan to subtract that, because since it was a positive number you want to subtract it from that side bc 700-700 is 0 which is good because you want d by itself then you do the same on the other side so 665-700 which is -35 so now you have a -d which is a negative since you want to suck the subtraction sign in so it is a negative d so now your equation looks like this -d=-35 so now you want to divide by -1 on both sides why? because a negative times a negative is a positive, which gets rid of the negative d and makes it a positive d so then you take -35 divided by -1 which is a positive 35 so yourequation now looks like d = 35 to check, add 665 plus 35, and do you get 700? yes so your answer is d = 35
