I think those are coordinates of points, (-5,8) and (-2,8)
so you just need to use distance formula ((8-8)^2+(-2+5)^2)=0+9=9
square root 9=3
Adding what rational expressions?
Angle e = x angle d = 5x supplementary means they add up to 180
x + 5x =180
6x = 180
6x/6 = 180/6
x = 30
so angle e = 30 and angle d = 5(30) = 150
3/8 as a decimal would be 0.375
THe amplitude is half of the distance from the highest and lowest phase of the wave..
4-(-1)=5
0.5*5=2.5
amp=2.5 units