Baker sold w cakes. If he had made x cakes initially How many more cakes did baker make than those he sold?
Let's denote the number of cakes Baker sold by s.

s = w

If Baker made x cakes initially then the number of cakes Baker made is x + s.

Plugging in for s we get that the number of cakes Baker made is x + w.

Therefore, the answer (symbolic expression) is: 

x + w