)=2
i keep confusing myself because of the negative. i'm not sure if i do it the first way or the second. pls

P - (-3) would turn into p+3. 

So we have 
p - (-3) = 2
become
p + 3 = 2

To isolate p, we need to move that "+3" over. To do this, we subtract 3 from both sides. Subtraction is the opposite (or inverse) of addition, which is why this works

p+3 = 2
p+3-3 = 2-3 ... subtract 3 from both sides
p+0 = -1
p = -1

So the final answer is p = -1

Add up all the sides