@@nbahn geometry equations can be hard when learning. I’d recommend going over the videos I’ve made for these shapes and rewatching. Write them down on paper a few times as well. Practice in multiple ways.

learn how they are derived and then you won't have to memorize, it'll stick natually

@@nbahn definitely a good question. It is an important base fact to know that two negatives make a positive when multiplied. I’d describe it this way. Multiplying a negative changes the direction of the other number. Already going negative, you’re flipping that over to positive. Graphically, there isn’t necessarily a way to show this. If you multiply an entire equation by -1, you are flipping all the terms around the equal sign, it is still the same equation and line.