Are my answers right and how would you graph this

You have the correct answers for all 4 boxes. Nice job.

To graph this, you'll need two points. 
Plug in t = 0
p = 100-5*t
p = 100-5*0
p = 100
So (0,100) is one point on the line. Think of t as x and p as y. In other words, (x,y) = (t,p)

Another point is (1,95) since...
p = 100-5*t
p = 100-5*1
p = 95

This equation is linear. You only need two points to graph. Plot (0,100) and (1,95) on the same coordinate system. Then draw a straight line through the two points.

No because if you do the higher number minus the lower number you will get a positive. if you do it the other way around you will get a negative number

The answer would he -4,-2 because the points are just on the opposite side. since the x axis is +4 it's going to he -4 and since the y axis is -2 it stays there because whaen rotated it stays in the third quadrant