Steps to solving: 
1) Rearrange! 
5+(-8)+(-5i)+(-6i)-(2+3i) 
2) Distribute! 
5+(-8)+(-5i)+(-6i)+2+(-3i)
3) Rearrange again! 
5+2+(-8)+(-3i)+(-5i)+(-6i) 
4) Simplify! [Let's do "i" first]
-3i+(-5i)+(-6i)= -14i
5+2+(-8)+(-14i)
5) Simplify! [Now do the constants]
5+2= 7+(-8)= -1
6) Refine!
-14i+(-1)