Click an item in the list or group of pictures at the bottom of the problem and, holding the button down, drag it into the correct position in the answer box. release your mouse button when the item is place. if you change your mind, drag the item to the trashcan. click the trashcan to clear all your answers. place the indicated product in the proper location on the grid. (x2 + 4)(x2 - 4)

 I'd suggest you focus on (x^2 + 4)(x^2 - 4). Note that this is the product of (the sum of a and b) and (the difference of a and b).

Note that (a+b)(a-b) = a^2 - b^2 (which is the difference of two squares).

Applying this to the given (x^2 + 4)(x^2 - 4), we get x^4 - 16 (which is the difference of two squares and is the answer you wanted.  

If you want to display this work on a grid, you'll have to find a way to share a diagram with your readers.