Angle B is 52 degrees
If they are vertical angles then A and B will equal the same angle 
To solve make this equation 
8x-4=7x+3
Add the 4 to the 3 on the other side of the equation 
8x=7x+7
Next subtract 7x from 8x 
1x=7 
Now we know what x is, so the last step is to multiply and add. 
7•7=49
49+3=52