Question 21930
There are a couple of ways to do this.  You might want to add x to both sides to get a positive x on the right side, and then subtract d from both sides to get the x alone on the right side.  


b-x = d
b-x +x = d+x
b= d+x 

b-d = d+x -d
b-d = x


x= b-d


R^2 at SCC