The answer is yes, you can use a weed wacker to mow your lawn. However, it is not the best tool for the job and it will likely create more work for you in the long run. Weed whackers are designed to cut through tough weeds, not delicate grass blades. As a result, they can end up damaging your lawn if used incorrectly. In addition, weed whackers typically do not produce a clean, even cut, which means that you will likely have to go over your lawn multiple times to get a clean look. For these reasons, it is generally best to stick to using a lawn mower when trying to achieve a well-manicured lawn.