A slope of 2 means rising 2 and run 1 on a graph. This would make x = 2/1. The + 2 allows the line to pass through (0,2) and therefore it will also pass through (-2,-2).
we know that 20% of the total is peters - and peter has 12 dollars. We know that 20% 5 times gets us to 100%. So we multiply 12 by 5 to get a total answer of 60$