(5, 10), its a data point, its fixed.
Note that x1 and x2 in above perceptron line are not same as (x1, x2) of data points marked as Positive or Negative.
Data points will lie on left or right of perceptron(almost always).
Based on your calculation., your perceptron classifier line is: x2 = 5.67x1 - 3.33. You can plot a line using 2 points (join them). And if you have equation of line you can randomly pick x1 to find corresponding x2. You chose x1=5, you got x2=25.02, so you have a point (x1=5, x2=25.02) on the perceptron classifier line. You can find one more point using some other values x1, once you have two sets of (x1, x2), you can plot it on a graph.
In short, (5, 25.02) is point on the perceptron classifier line whereas (5, 10) is a data point. Better use x1 different from 5 (for points on classifier line), it might be less confusing.