First of all, we should think that the questioner should test your knowledge and then look for information from the stem of the question. We must make a good picture of such a problem.

Analysis: y=x+b, we can know that the slope is 1, then the angle between the straight line and the x axis is 45 degrees, then the angle OBA=60 degrees.

In this way, you can get tg30=b/5 by oral calculation, so b=5/3* root number 3, hehe, the input is very troublesome.