Short Answer 
The process involves selecting an item and dragging it into an answer box, or discarding it by dragging it to a trashcan icon. Additionally, to calculate the distance AB after applying a transformation, you identify coordinates for points A and B and use the distance formula d = √((x2 Рx1)² + (y2 Рy1)²).
Step 1: Select and Drag an Item
Begin by locating the item you wish to use from the list or group of pictures at the bottom of the page. Click on the desired item and keep the mouse button held down while you drag it towards the answer box. This action allows you to position the item accurately according to the task requirements.
Step 2: Place or Discard the Item
Once you have moved the item into the answer box, you can release the mouse button to place it securely. If you change your mind about the selection, simply drag the item over to the trashcan icon to discard it. To clear all selections at once, click directly on the trashcan.
Step 3: Calculate the Distance AB
To determine the distance AB using the transformation T: (x, y) → (x + 2, y + 1), identify the coordinates for points A and B based on this transformation. Once you have the coordinates, you can use the distance formula d = √((x2 Рx1)² + (y2 Рy1)²) to calculate the distance between the two points effectively.