In the xy-plane, the point (6,3) is the midpoint of the line segment with endpoints (x,5) and (9,y). what is the value of x+y?

The formula for the midpoint of a line is 
x1 + x2            y1 + y2
  ,        
     2                     2

so x+9 / 2 = 6  and     5+y / 2 = 3

so x = 3 and y =  1

x+y = 4

Where the white dots are is where your points should be plotted.a translation is simply just moving something from one place to another. in this case, you would move each plot point of the original shape 2 units up, and 5 units to the left.